This is where I really prefer the European model[1] - you heat the whole house with hot water. You make hot water with cheap natural gas. If you're lucky enough, you can even use geothermal.
Then you use insulation. This especially is something that feels nobody in the US has heard of. At least in California.
As a result, your radiators are turned down to 2 out of 10 all day (heating turns off automatically overnight), and you have to sometimes open a window when it's -13C outside so you don't sweat.
Now I don't know how much people spend on heating when they live in a house house, but my apartment's heating bill this winter was about 30 euro a month[2] and I had to keep all my radiators turned off because the one in the bathroom couldn't be regulated. So that alone was enough to heat everything to extremely comfortable levels.
tl;dr don't heat with air, insulate your fucking house, and install modern windows
[1] Could just be where I'm from, but it seems fairly common in Europe and not at all something I've seen in the US
[2] I think my gramps spends about 2k euro in October to pay for natural gas that heats his house until some time in April. So about 300/month for a ~10 bedroom house because he's got a house that's way too big.
> Then you use insulation. This especially is something that feels nobody in the US has heard of. At least in California.
In defense of Californians, most of us rarely, if ever, turn on a heater and most homes here don't have AC. Our heating and cooling costs are a small fraction of those of you who live in places that have seasons.
> > Then you use insulation. This especially is something that feels nobody in the US has heard of. At least in California.
There's lots of poorly insulated homes in California, either because they are old or cheaply-made, or because they are in places that have milder weather where it is less necessary. But there are also lots of well-insulated homes in California.
> In defense of Californians, most of us rarely, if ever, turn on a heater and most homes here don't have AC. Our heating and cooling costs are a small fraction of those of you who live in places that have seasons.
As a Central Valley resident, I think you may be falsely generalizing from "the Bay Area" to "California". Even cheap homes in the Valley usually have AC, even if its not central AC.
My 2 bed apartment, with both people working from home pretty regularly, and floor-to-ceiling windows on one side, costs < $30/mo for electric + gas except for 2-3 months in the winter, when it rises to $60 or so. Though we have no tv and no a/c. (last bill: 5.8 kWh/day)
Given those costs, it's very difficult to get a return on better insulation or insulated windows.
I don't think it's only the Bay Area. I've lived in parts of California that between them add up to about 70% of California's population, and not one of them had A/C prevalent, from San Bernardino County to Santa Cruz County.
That really depends on where in the state you are. Coastal cities, generally, more so. Inland, even within the SF Bay Area or Los Angeles, you'll find a lot of AC, and in the Central Valley it's a huge determinant of load and peak load.
> In defense of Californians, most of us rarely, if ever, turn on a heater and most homes here don't have AC
Then why on earth was I freezing my balls off in Menlo Park this November? The weeks before we realised our house even had heating were miserable. And even afterwards, as soon as the heaters weren't blowing hot air, or you were more than 3ft away, you were instantly cold and miserable.
Had you previously lived in more equatorial climes? Temperature preference really is about what you're used to. Some years ago when I visited India in January/February, my friends' relatives in Rajasthan were shivering in sweaters and coats while my friend and I were perfectly comfortable in short sleeves.
No, I previously lived in a climate that goes up to 100F in summer and down to 5F in winter. But I've always lived in a proper house with heating and insulation and whatnot.
New Zealand's North Island has a similar problem. A typical house has cheap construction with thin exterior walls, unfinished crawl space with exposed soil, no insulation and no heat pump. Coupled with a damp climate 5-25C, in the winter one gets heavy condensation, black mold, chills, and the fingers don't work.
I bumped into a guy here from Northern Germany who said he's never been so cold as in a kiwi house in the winter.
The NZ government is trying to change minds, but I still see houses going up with empty wall cavities and no air barrier. But then, the natives wear shorts and tees outside in 5 degree weather all winter. So, maybe its just me.
> You make hot water with cheap natural gas. If you're lucky enough, you can even use geothermal.
In Denmark it's getting pretty common to produce it via trash incinerators. They produce a kind of heat that is apparently that not great for electricity generation, but pretty good for district-heat production. So much so that the price of unsorted municipal garbage in both Denmark and Sweden has risen in the past few years, because it has become a valuable energy source.
CHP (combined heat and power) or district heating, typically, though I'm not sure which applies in your case.
Most areas which have implemented a trash-to-energy program pretty soon run out of high-grade suitable trash and resort to imports. Entropy always wins.
As others have said, try cooling a house with rads. It's not like North America is oblivious to radiators; they were very much a standard way of heating houses before the popularity of AC made forced air a much more logical choice.
> Then you use insulation. This especially is something that feels nobody in the US has heard of. At least in California.
If you only know about the completely unrepresentative California, why expose your ignorance by projecting to all of the U.S.? And further, why bother calling it "the European model"? Obviously the way houses are built, insulated, and heated in a country like England or Norway is going to differ wildly from how it's done in say, Greece.
Even within California the climate differs so much that there are 4-5 different building codes for insulation. But in general, the minimum code for insulation in California is around half that of states with colder climates (e.g. R30 for ceiling in California, R50 for Wisconsin).
> And further, why bother calling it "the European model"?
Because I've seen radiators and decent insulation in literally every house I've ever been in anywhere in Europe. Warm places like Greece and Portugal included.
Differences are mostly attributable to the age of a house rather than its location. But arguably old stone houses (200+ years) in hot places have the best insulation in that they are simply built with 1m+ thick walls and super tiny windows.
Insulation. It works. For both hot and cold.
Granted, the moderner your building and the thinner walls and more cement it uses, the likelier you are to need AC in summer. In old buildings you get enough cooling by just airing the house overnight and keeping everything closed during the day ... unless of course you have a big computer in your room. Then you're screwed.
> As others have said, try cooling a house with rads. It's not like North America is oblivious to radiators; they were very much a standard way of heating houses before the popularity of AC made forced air a much more logical choice.
I've always found the popularity of AC in the US bizarre, every single European who've traveled to the US in the summer and had to spend extensive time inside complained about the cold and quickly switched to long sleeves and trousers.
Forced air heat is a lot more common in the U.S. because we are further along on adopting air conditioning. If you put in ducts for AC, it's cheaper to use those to distribute heat. Upscale construction does seem to be adding radiant floor heat.
Houses are generally pretty under-insulated though.
Air is a pretty bad transport agent for heat compared to water. To heat a house (and especially poorly insulated ones) the air either has to be rather hot or flow pretty fast. The former is not very comfortable because of the large temperature gradients and it can cause a 'scorched dust' smell. The latter is also not very comfortable when you're in the flow path, it's noisy and the increased flow of air in the room means more heat is escaping to outside.
It can work for well insulated and airtight houses but I'm not a fan (pun not intended) because you're tying two different functions (heating and ventilation) together.
Also, if you're in an apartment your place might be so hot because you have a neighbor that has cranked the heat. I used to be able to keep the heat off in a place I lived at because the person that lived below me had their place like a sauna.
its done that way in Russia as well, at least in the city. the downside is they have to turn off the hot water occasionally to do cleaning, which means no hot water for 1-3 days.
in village homes they use pechkas [1]. a giant radiant heater that uses firewood and sits in the middle of the home. most are adapted so that you can use them to cook too.
In moscow, they do this in what is (nominally) summer for almost 2 weeks. I thought the water would be chilly, but if I took brisk showers I'd be ok. The first time I tried I nearly gave myself hypothermia -- no exaggeration, I was under a blanket unable to stop shaking for 10 minutes -- and figured out why I saw kettles in people's bathrooms when I was a guest in their apartments. Thank god for the gym which was in a different area of the city.
Crappy insulation is the norm here in Australia as well, which is more of a problem down south where it gets cold in winter. I used to work with a Scot who highlighted the issue, saying that in a Scottish house, the insulation was good enough that you could basically heat a room with a candle.
I once asked him if there were any wooden houses in Scotland, he replied "Yes, we keep our lawnmowers in them".
There's another historical difference between Scotland and the US here: the US has a near-unlimited supply of wood, while Scotland was mostly bare of trees by the 18th century.
Much cheaper to build walls from local stone and save the imported wood for the floors and roofs.
> I once asked him if there were any wooden houses in Scotland, he replied "Yes, we keep our lawnmowers in them".
Austro-hungarian empire outlawed wooden houses in the early 19th century. Hence we still don't have any, and if you live in a wooden house[1], you are considered to not have been able to afford a proper house and thus looked down upon.
[1] becoming common with drywall construction methods. Particularly because it's cheap and fast.
Imagine how much more they could save by keeping the heated mattress pad on and never leave the bed! I mostly jest..
The author seems totally unaware of the efficiency gains that a heat pump can provide. A 300W space heater will be easily outmatched by a heat pump that consumes 300W (unless we're dropping way, way below 0C). The efficiency is likely ~3x [1]. I hope the author isn't making this mistake out of disdain for centralized hvac, since window unit heat pumps are readily available for small spaces.
Without looking into specifics I decided that a couple of small well placed space heaters (in rooms with traffic) might save electricity over the whole house heat pump.
I had 3 small space heaters that ran most of the day and night and I turned the heat pump down to 50. I was wrong. My electric bill was higher than just running the heat pump, and most of the house was cold most of the time.
He is dealing with -30 below winters at which point most heat pumps are almost useless. A ground source heat pump can still be useful but they cost quite a bit more to install so they might not be worth it if your to far north.
Spot-heating, especially within a leaky building envelope utilizing expensive heat sources (electric resistance) is one option.
But it's hardly the only one, or the best. For northern climates, taking a whole-system approach to home/structure design gets you a tremendously greater payoff in terms of energy savings.
Among the most powerful demonstrations of this I've seen are Thorsten Chlupp / Reina LLC's experiences designing and building zero net energy homes in Fairbanks, Alaska.
His videos are long (~90 minutes) be exceptionally comprehensive. The TL;DR is:
• Total envelope. He pays exceptional attention to any thermal envelope penetrations. All emissions (air, water, sewage) pass through thermal exchanges.
• Thermal mass. The foundation, flooring, central masonry stove, and a 5,000 gallon stratified thermal storage tank all store and scavange thermal energy both passively and actively.
• Moisture control. Heat barriers introduce thermal issues. Chlupp makes use of multiple glazings, window setbacks, and _exterior_ thermal shutters to minimize moisture buildup on windows. Moisture barriers and ventilation of interstitial spaces is designed to clear moisture.
• Heat pumps. Rather than create thermal energy directly (other than the masonry stove), Chlupp moves heat using ground-loop heat pumps.
• Solar and net metering. Solar panels (yes, in Alaska) and net metering help him arrive at net zero energy. His first-year goal wasn't met due to plug-in hybrid vehicles, an oversight in his energy modeling.
Though conceived as a whole-system ground-up greenfield design, the principles are applicable to a lesser degree as retrofit options.
Oh, and for heating your bed: a 1 liter Nalgene bottle, filled with boiling hot water, and slipped into a wool sock, will heat your bed cozily. Two are almost certainly too hot, but you're welcome to try. And they'll last the night.
In a well-insulated, well-designed house, you won't have any worries about frozen pipes, even with a low thermostat temperature, since all pipes will be inside the insulated enclosure.
Some of these people are ex-hippies or hippie-ish, and there is a bit of bullshit out there, but there's certainly plenty of better ways to build and renovate homes for energy efficiency.
I'm currently living in a passive house (in Belgium, Europe). We've only moved in two months ago so we haven't experienced a winter yet but even in the current summer climate it has already been an order of magnitude more comfortable than any of the other places I've lived in. When the temperature hit 30 degrees Celsius for a couple of days last week the house was at a comfortable 23 degrees. Everywhere.
Key design points:
- Insulation, insulation, insulation. We have 30cm cellulose in the walls and 36cm in the roof plus some 5cm fiberglass in the space between the walls and drywall.
- Airtightness, in combination with a ventilation system (with heat recovery).
- Large windows (triple glazing) on east, south and west sides to get free heat from the sun in the winter but have some screens to keep the sun out in the summer.
- We use a geothermal heat pump to prepare hot water and to be able to heat the house a little bit in the winter when needed, using underfloor heating pipes. Extra bonus that has turned out to be essential: we can use this system to passively cool the house by simply pumping the water through the pipes and into the ground. This can lower the temperature in the house by several degrees in an energy efficient way.
Based on our energy consumption for the two months we've lived here we'll end up at around 3500-4000kWh per year. And that includes everything: heat pump, ventilation, all electrical appliances, ...
Building such a house isn't rocket science. The materials and techniques are well known and readily available (at least here); it's mostly a matter of good planning upfront and paying attention to the details when executing. Not all construction companies are up to speed but they're slowly getting there (or they'll disappear).
As a matter of fact: the EU has mandated that by 2020 every newly built house must be more or less equivalent to a passive house.
Chlupp's design borrows very, very heavily on passive house concepts.
And he uses massive amounts of insulation. He creates a large (big enough to walk in) wall cavity, and fills that with blown cellulose. I think it's on the order of twenty tons of cellulose. Not only does it insulate, but it forms a thermal mass.
Similarly for his foundation: a large sand base as I recall, then a slab, which create yet more thermal mass. The masonry stove at the building core is another, and finally a 5,000 gallon vertically-arranged water tank. This has a perforated distributor, and the idea is that he circulates water through his masonry stove and solar thermal panels whenever the output of those is warmer than the water at some point in the tank -- it tends to be ~120F near the surface, and ~40F near the bottom. The water stratifies according to temperature, and he banks his BTUs.
In our case it's something like five tons of cellulose. It's supposedly a good buffer against summer heat getting into the house but it doesn't really store heat to release it slowly when the temperature goes down again. I can imagine it works well high up north but here I think it would make it more difficult to control the temperature. It's one of the reasons why we have chosen a wood-based construction using I-joints. We do have a concrete foundation slab, screed everywhere and ceramic tiles on the ground floor.
The big stratified water tank is a well known concept but you need to have room for such a big tank. Here in Belgium space is at a premium so houses tend to be on the small side. Solar thermal panels are often connected to a tank of 500 litres or less, simply because of space constraints...
There are several possible construction models; it's a matter of selecting one that fits your local climate and your habits. Not everybody likes a stove for example.
The last couple of years we've seen a shift happening from applying the passive house concepts on new houses (pretty much a solved problem) to renovating existing ones. Here in Belgium there's a massive amount of old houses constructed before the seventies/eighties which is when they finally started putting in insulation. Now that all new houses are energy efficient it's time to tackle the massive waste in those old houses. Most people buy such an old house and start renovating so there's a lot to be gained.
In Chlupp's case, he pretty much designs his structure around the tank, it's integrated to the building core.
An alternative he points to in Europe is a community / neighborhood storage, where a thermal storage tank serves a number of homes. Another option is seasonal thermal storage using ground-base storage, where you've got suitable geology (no moving water table to whisk your heat away helps a lot), used in at least one instance in Canada. Heat is pumped in during the summer and extracted in the winter, as part of a ground-loop heat pump.
I live in southeast Alaska, where heating issues can make or break your ability to pay rent or afford a mortgage.
Most homes are heated using fuel oil. We moved into an awesome old house last summer, and we were worried about heating costs. The landlord had a heat pump installed last fall. I'm sure we would have had some $300-$500 heating bills (per month) last winter if we were using oil, but the heat pump never cost more than $150 per month.
That was a relief, because we spent one winter in a drafty house with a malfunctioning boiler system. That was not fun at all, and we moved out just because of heating costs.
I'm hoping to buy a house sometime in the next few years, and the first thing I'll do is complete a thorough heating overhaul of the house.
Take a look at the presentations I listed above. Chlupp eliminates the furnace / heating system entirely.
It's one of his design goals. Minimizing your furnace requirements (but not eliminating them) gives you progress, but it remains a major expense (for installation and operation). Eliminating it entirely addresses a huge cost element for northern construction.
I don't live in Alaska myself, and can't speak to the full validity and credibility of his work, though it seems pretty solid. But I'm absolutely impressed with his attention to detail and the specifics of his methods and approaches.
Ground Loop or air to air heatpump? What brand and model?
(I ask because we just bought a house in montana and are thinking about a heatpump before winter...we have propane radiant heat now. We'd want one that would work with cold temps though it rarely gets bellow -10 F here.)
It's an air to air Fujitsu. I'll check on the model when I get a chance.
Most of our winter weather hovers in the mid 30's, day and night. We get occasional cold spells in the 20's, but it's rarely in the teens and I've seen single digits once in twelve years here. I don't think it's ever been below zero here.
It was interesting to get used to the heat pump just being on low all the time. Our monitor stove would come on in bursts, and you'd notice a steady heating/ cooling cycle throughout the day. The heat pump just puts out a steady, slightly warm airflow all day long.
I'm not sure how heat pumps behave in colder climates. Our landlord did not remove the monitor stove when he had the heat pump installed, and it was nice to know we could fall back on the monitor if the heat pump was not putting out enough heat. You might consider leaving the propane system in place this winter if you do try a heat pump. It might just give you a little peace of mind about not having an issue in the middle of a cold spell.
Feel free to send an email if you're curious to ask more.
Don't use boiling water with hot water bottles; the ones you can buy have warnings about this (it can damage them). Just use hot water from the tap (which hopefully should be more efficiently heated than however you boil water as well).
Don't worry about energy consumption; it's negligible for the hot water bottle, and for the electric blanket as well, especially compared to keeping your house heat up high at night. Not really worth debating, though do note: the hot water bottle has a fail-proof, gradual, automatic shutoff, it fits any size bed, requires no electric outlet, requires minimal storage space during warmer months (so you can have an extra for guests), and has an initial investment of, like, $4. :)
The thing about bottles is that they're cheap, multi-purpose, very specific, don't have cords, pose no fire / tripping / electrocution risk, can be moved about, etc., etc.
A highly effective low-tech solution.
Yes, the efficiency of heating the water in the first place may vary, though that's energy that's almost certainly delivered to your residence space, so in that regard it's pretty much a wash.
What I've found is that a liter bottle packs a goodly amount of heat, the sock regulates the release just about perfectly (and keeps you from scalding yourself against it), and the result is quite toasty. There's also nothing quite like having warm toes in bed.
The bottles are still warm in the morning under a good duvet.
Electric blankets can burn you and the whole house down and do not use the same form of heat transfer https://en.wikipedia.org/wiki/Heat_transfer. They just should not be used.
The egress path of that heat will tend to be dissipation throughout the habitable area, modulo circulation. One factor I've noted in room heating is how much heat tends to rise toward the ceiling. A vertically-oriented fan (need not be a ceiling fan) will help achieve a good blend of temperature floor-to-ceiling.
Air flows between rooms / through doorways can also be surprisingly stubborn, but it does happen.
The specifics will depend on the size of the interior space, position of the kitchen, access to exterior walls, etc.
People should check out WattVision. It's a little device that attaches to your electrical meter so you can monitor your electrical usage.
What I've found is that almost all of our home's electrical usage comes from heating (heaters, clothes dryers, and hot water).
Everything else is almost a rounding error. For example: I saw almost no change when we switched from incandescents to LED lighting (even in the summer when we're not heating the house) but I saw a large change with efficient shower heads and washing clothes on cold.
Incandescents heat the room at the ceiling, which I would imagine significantly reduces their effective efficiency relative to a well placed electric heater. Also, of course, incandescents have the same poor system efficiency as other electric heaters, compared to burning the fuel for heat in your house.
Totally heating dominate energy use. I'm rather disturb to hear people pay much attention to so call "phantom power" from idle electronics and adapters. Adapters plugged in the socket do not consume measurable power. Wifi router uses about a few watts. The worst offender is a set-top box that uses 18W irrespective of power on or off. It is piece of crap anyway so I unplugged it. All the electronics in the house probably use less power in a day compare to running a 1500W heater for 15 minutes.
Not really. It used to be true in the 1970s; but today appliances consume roughly about the same as space heating, despite decades of energy efficiency improvements --and the culprit is, you guessed it, the rise of consumer electronics [1,2].
And it's not just standby-mode "phantom consumption", as the EPA used to think. Today there are more devices with larger, sharper screens and hungrier batteries to charge, all left on for longer than ever before [2]. And it all adds up.
Fortunately I have natural gas for heating and hot water. Much cheaper than electric heat, but the local gas utility is still charging me about $12/MMbtu, which is about 3x the Henry Hub spot price.
But electronics is not nearly as benign as you suggest, it depends on your lifestyle. E.g. I have 4 TiVo boxes running 24x7. Each draws about 40W. In my area 1W works out to about $1/yr. So my TiVo boxes cost me $160/yr just in electricity.
I also believe that LED lighting saves money. In our family room I used to have a 75W light bulb on for at least 12 hrs/day. That's $37/yr for just a single bulb. I replaced it with an 11W Philips LED. It's now costing me $5.50/yr. That's an over $30/yr savings on a single bulb. The same savings applies anywhere light bulbs are on for a long time.
I carefully measured everything in my household. Nothing come close to a space heater. Most small electronics use negligible amount of power. We should not need to pay any attention to them.
There are probably a separate category of problematic electronics that really sucks power. I was offended to find my set-top box suck 18W. I am doubly offended by your array of Tivo boxes. For 40W, my laptop will be doing computation intensive task with the fan running loudly. My mac mini consume only 11W when idle. A big huge TV would use power. I only have a 32" TV and I use it only a few hours a day at most anyway.
This cold winter in Chicago I tried an experiment where during the day I just heated one room with an electric space heater (a Vornado) and let the rest of the house get to 50 F. It ended up saving me exactly $1 because turns out electricity is $$$ and I discontinued the effort.
In my experience thermal underwear (long johns) should be considered a must during winter. You don't have to live in a place like Canada or Minnesota to make them a standard part of your wardrobe.
OK, Paul Wheaton simply doesn't know what he's talking about:
"I think that this does produce some savings, but not as much as you might think. If you set your thermostat to a constant 70, the heater works a little at a time throughout the day. If you drop it to 50 at night or in the middle of the day, the heater stops working, but then when the time comes to warm the house again, the heater has to work at full power for a long time to get the temp back up - thus losing a lot of your savings."
If you're running heat constantly, you're maintaining a constant flow of heat from your interior to the exterior. That is, you're maintaining a high heat exchange rate to the exterior, and you're constantly wasting a large portion of heat.
If you're heating only while you need a warm interior, then as the interior temperature falls, the energy flux to the exterior decreases. You're no longer pumping heat into the external environment.
Yes, you'll run your furnace/heating system continuously for a while in raising the interior temperature, but that is largely adding heat to the interior space, not to the exterior.
The net is expending less energy.
Your most efficient strategy is to turn interior heat down to the minimum essential level (ultimately: enough to keep pipes from freezing), or the minimum level the thermostat allows (often ~50F in the US). My own practice is generally to turn any heating system off entirely at night.
From a moisture management perspective, you also win as cold air has a lower absolute humidity, that is, the quantity of water it can hold is lower. Heating cold humid air reduces the relative humidity, allowing walls and surfaces to dry out.
The overnight heat loss is also a very clear sign that Paul Wheaton is dealing with an exceptionally poorly insulated structure. And a very poor grasp of thermodynamics.
The same principle holds for AC as well, though here you want to increase the temperature setting at which the AC comes on, or disable AC entirely while you're out of the home.
A better way of thinking of this is to minimize the energy input (heating or cooling) when it's not needed.
His article on CFLs (http://www.richsoil.com/CFL-fluorescent-light-bulbs.jsp) is very cringe-worthy as well. As part of his argument, he references a report he heard of claiming that kids gained 20 IQ points by switching back to incandescent bulbs. Seriously.
My thoughts exactly. Started reading on the site a couple of weeks ago after an article about lawns on HN (which was reasonably ok and correct). His CFL article starts ok, and he does make some good and valid points but then the pseudo-science and false logic kicks in to levels that make my cry.
wikipedia: "In order to be effective as an insecticide, diatomaceous earth must be uncalcinated (i.e., it must not be heat-treated prior to application)[13] and have a mean particle size below about 12 µm (i.e., food-grade – see below)"
Its used occasionally for deworming people and considered a low risk insecticide. Just because you can eat it and it has some benefits in use cases doesn't mean you should consume as much as you can. Its the classic vitamin snake-oils sales pitch, "X is good for you thus more of X must be better for you"
I've encountered advocates of DE consumption previously. No real sense of whether it's legit or bogus, though there seems to be some plausibility. I'd have to look into other sources. Wheaton's credibility based on his other statements isn't great, and dosing and/or specific indications would be useful.
It is helpful to realize that in a pre-industrial society, parasites were very common among humans (and still are in less developed nations), including many introduced via food. Whether or not DE could combat that is arguable, but a regular intake might be argued if you're subject to parasites in your food supply. I'm more in favor of alternatives such as cooking.
It could be true if switching from 60 Hz old-style fluorescent tubes to incandescent. Working with 60 Hz lighting for those of us that can clearly see the flicker is very difficult. It's literally like trying to work under a strobe. Even at higher rates these lights have random flickering from age and other reasons. You may not consciously see flickering, but your brain does.
Your theoretical analysis misses an important physical fact: houses are able to exchange air with the outside world, not just heat. As you heat a normal room, it will expel air in order to maintain constant pressure, and similarly, as you allow a room to cool, outside air will enter again to keep the pressure constant.
There was an article about this in the American Journal of Physics [1, 2] a couple years back, and the authors calculated that heating a room from 273K to 300K (32F to 80F) causes it to expel about 10 percent of the air inside it.
Somewhat surprisingly, the authors don't comment on how relevant this is to the question of when to turn your heater off. The fact that allowing a room to cool draws in cold air from the outside means that the practice is worse than you would naively think, but I don't know when if ever that actually suggests leaving the heater on a constant setting. I'd be very curious to see someone extend the calculation to give an answer.
I have been told by multiple HVAC professionals recently that one should keep their fan on their system always running. They have in fact adopted this practice at our offices and it greatly help with keeping temperatures in consistent from room to room.
The arguments they provided for this were:
[1] Constant air flow creates more consistent temperatures (less highs and lows from interior to exterior or floor to floor.
[2] Allows filtration system to work continuously cleaning the air.
[3] (This is the one I am skeptical of) Starting the fan motor has a large current draw, but leaving it running is very low current on modern high efficiency HVAC systems. Also apparently when the fan starts i the most likely time for fan failure due to high current and torque on the motor. These fan motors are typically not repairable in small commercial and residential units and are quite expensive.
We adopted the fan always on with scheduled temperature adjustment here at our office, it is more comfortable for sure and less dusty. I do not know if it affected energy costs. When I tried this at home it was more comfortable but my electric bill went up by ~$20
For offices, it's likely more a matter of keeping pockets of hot/cold air (or other quality issues not related to temperature) from forming. Even just with lighting and office equipment, there's a fairly considerable energy flux into many office spaces, and without mixing you'll tend to get uncomfortable pockets forming.
Your #3 point strikes be as fairly valid: large electric motors do impose a very high load, and the current draw could be harmful to the motor (and switching / control circuits), while the imposed load might also be hard on other equipment. I doubt the energy usage argument (for cycling the motors off) really carries much weight, and it should be possible to idle such systems at low power. For most commercial buildings, you've got systems for heating, chilling, and air handling which are pretty much all operating simultaneously: you have a need for hot and cold air in different places, there are mixers which will deliver what's needed where it's needed (at least in theory), and the fans blow all the time.
Though I've only a pretty glancing familiarity with HVAC in general, not particularly my area of expertise.
I run the circ fan all the time as well, but the bearings on the motor do have a limited lifetime. Ask me how I know this.
A new motor will cost hundreds of dollars, more so if the blower and fan cage are a single assembly. You'll need to amortize that cost into your comfort level.
It will also quit at the least convenient time, following a combination of Tuttle's and Murphy's Laws. Again, ask me how I know this.
About 3, the idea is right, but they're probably overstating the difference between starting power and running power.
Starting a motor is not something you do lightly for bigger motors (but big like a subway or a car) but I doubt they're that heavy for it to be a big concern.
My bet is that it'll spend the starting power in around 5s of running, tops.
This effect isn't going to be very significant. A constant exchange of air will have a significant effect, but a one-off exchange of 10% of the air will be negligible. The reason for this is that the air has a very small thermal mass compared to the building structure.
I've got mote sensors in every room in my house, including the hall. When my kids leave the front door open in winter for a few minutes, as kids tend to do, I can see the temperature in the hall dive on the graphs. But close the door again, and the temperature is right back up very close to where it started in just a few minutes - even when the heating is off.
The heat loss due to thermal expansion and contraction of air will be quite minimal.
Thermal density (specific heat) of air is going to be ~1000x less than that of solid objects.
The specific heat of gypsum (the primary constituent of drywall) is 1.09 kJ/kg.K
For dry air it's 1.0 kJ/kg.K
Air's density is 1.225 kg/m3.
A 6m x 9m x 2.3m (20' x 30' x 7.5') room has a volume of about 130m^3, so a 10% exchange would be 13m^3, or 16kg.
That's about 15 kJ of heat energy per degree C, or roughly 0.0004 liter (0.0001 gallon) of heating oil equivalent.
The drywall would be (in feet) 20x7.5x2 + 30x7.5x2 + 20x30 ft^2 (I'll assume the floor is some perfect insulator for now, and that the room has no doorways), and 1/2 inch thick, or 1.6 m^3. That's about 3600 kg of gypsum, which has a heat capacity of about 4000 kJ per degree C, or about 0.1 liter (0.027 gallons) of heating oil equivalent.
cheap apartments are also poorly air-sealed, which means they're already losing a great deal of their heat through air leaks. An extra one-time 10% turnover won't make a puddle of difference.
In winter in particular, the rate of through-roof air leaks is also greater when temperatures are warmer due to the stack effect. The author is completely wrong on this front - it's far better to let your house cool down and then re-heat.
The only time this isn't true is if you have a two-mechanism heating system such as a heat pump with resistance heat backup, where a large temperature swing invokes the more expensive resistance heater. The author doesn't.
...but the ideal structure is not supposed to exchange air with the outside particularly because of this. That is why windows and doors have seals on them. I'm no mechanical engineer, but I've worked with enough of them in my career to understand that their goal is usually keeping a structure tightly sealed when ingress/egress paths are closed (of course opening windows/doors is a choice of the occupant, which if your striving to reduce heat loss/gain... you shouldn't do)
An ideal structure should minimize convection, but rooms for people really can't be allowed to undergo large changes in temperature without exchanging air with the outside environment, because that would imply a large change in pressure.
A 10 percent increase over atmospheric pressure might not seem like that much, but it's enough to notice, and would probably be uncomfortable. It's like being under 1 meter of water. It's also enough to break large windows.
I don't think comfort would be much of an issue given a slow adjustment period, but structurally it would be ludicrous. You'd be unable to open or close doors. Your walls would have to be built a hundred times stronger than the walls of a normal house. Any breach in the pressure envelope would be a miniature version of Aloha Airlines 243.
This is, by the way, why hard drives have filtered air holes rather than being completely sealed.
"the ideal structure is not supposed to exchange air with the outside"
No, the ideal structure should minimize heat loss from air exchange.
I'm not fully up on my air exchange rates, but it's fairly typical for ranges to be in the 4-20 range, that is, the interior air is exchanged with the exterior 4-20x per hour.
In my Thorsten Chlupp references elsewhere you'll find he makes extensive references to heat exchangers which minimize thermal losses. He does this by a twofold process for his Fairbanks, AK, homes: entering air is routed first through the ground where it's heated from very cold ambient temperatures of as low as -40C / -40F to a temperature closer to freezing (~0F). It's then passed through a heat exchange where the exiting warm air transfers much of its heat to the entering cold air.
The purpose of tightly sealed windows and other possibly entry/exit points isn't to eliminate air exchange so much as to control it: you want air entering and exiting through your designated ventilation systems and transferring heat properly, not traversing the envelope arbitrarily.
Another way of putting it: A well-designed structure should minimize random, unintentional air exchange, but provide sufficient deliberately-engineered ventilation to keep the air and people happy. For efficiency, that ventilation should go through a heat recovery ventilator (HRV) or energy recovery ventilator (ERV) as appropriate to the climate and budget. (An energy recovery ventilator also exchanges moisture).
Beyond Chlupp, Lstiburek is a great engineer and writer on these topics.
Perhaps I lacked the verbosity in my original comment, but this was what I meant to imply: ventilation is part of the design. Unintentional exchange is to be avoided.
>...but the ideal structure is not supposed to exchange air with the outside particularly because of this.
With regard to letting a house cool down at night, that's impossible. If you heat a quantity of air from 273 K to 300 K at constant volume, the pressure increases from 1 atm to 1.1 atm. That may not sound like much, but it's better expressed as a pressure differential of 10 kilonewtons per square meter, and the surface area of your house is such that it could severely damage the walls and blow the door open -- popping it like a balloon.
(The fundamental mathematical error made by those who minimize this effect is ignoring the surface area of the building)
It's most definitely not the goal to suffocate the inhabitants, no, and the goal also isn't to have the natural humidifiers living inside create a tropical climate ripe with microorganisms and stuff. Yes, you want to avoid excessive air exchange because you'd lose a lot of heat that way, but tightly sealing a house would be a very bad idead indeed. If you do make the outer envelope essentially airtight, that gives you very low energy consumption and is part of the passive house concept, but then you need active ventilation, which obviously implies a hole in the envelope, and thus will keep the pressure inside equalized with the pressure outside (modulo a small differential caused by the ventilation itself).
Funny how these things have been well solved in places with real winters (or summers) for hundreds of years isn't it?
Central European buildings used to have walls so thick as to achieve a cave effect, which gave them nearly constant temperature through most of the year. With some minimal-ish heating during winter as a side-effect of cooking with wood to combat the effect of bad windows.
Not sure if your comment was a general statement or aimed at the author of the article (Paul), but for the record Montana has "real" winters. I lived a much similar life in rural Utah for many years, doing many of the same lifestyle optimizations that Paul is engaged in.
I don't know what Paul's house is built of, but mine was solid brick, which probably matched the structure and function of the dense brick/cob building of Europe. The thermal mass was a blessing, as my only form of central heating was wood/coal-burning cylinder stone in the center of the home. In the dead of winter (lows often in the -5 to -15F range at night), a short, intense burn first thing in the morning would charge the house, with minimal burning during daylight hours to maintain a comfortable temp around the core living areas (55-to-65F). Just before bed, load and tweak the stove for a long slow burn. By morning, even on the coldest of nights, the temp never dropped below 45F.
As for his heat-the-person-not-the-room method, that's an obvious, old technique which I applaud Paul for using. For me, a thick down comforter on the bed pre-charged with heat via old-fashioned hot water bottle an hour before (they have nice, newfangled silicone models these days) was all it took. The water was, of course, heated on the wood stove.
During the day, wise clothing (layers, wool, hats) and space heating made the place livable. As did the occasional bout of labor to build up head (an old saying is that chopping wood heats you twice). Yes, there is also some acclimation that takes place. Several years after abandoning the lifestyle, I still cannot tolerate indoor temps much warmer than 70.
Frankly, given that Paul has a rocket mass heater (much, much more efficient than my stove ever was), I am surprised he needs much in the way of spot-heating. Unless his home is of stick/frame construction.
In Austria and parts of Germany, rural houses have huge eaves. Wood is collected and stacked under the eaves providing extra thick walls/insulation during the winter.
Sure, if you have shitty insulation. The proper strategy is to have good insulation, and then to have the heat on constantly using a CV system at low temperatures, because heating constantly with water of 30 degrees (C, that is) is much more energy efficient than heating in peaks with much warmer water (60, 70, 90 even 20 years ago). So yes, in houses with crap insulation warming constantly is less efficient. However in properly build houses, warming constantly is more efficient. (I'm living for a few months in New Zealand - oh my the quality of the houses here is atrocious. It's one of the main reasons I couldn't live here permanently. And then they put in a 'heat pump' (an air to air one) and call themselves 'green'. Don't get me started.)
How can heating be any less efficient than 100%? I get that engines can be less efficient than 100% since the remaining energy is dissipated as heat and heat is the not desired energy in that case.
What happens with the remaining energy if you heat with less than 100% efficiency? Does it start to rotate things?
Heating can be more than 100% efficient. Before you go "what, lol, no" - let me clarify. Obviously it can't be even 100% thermodynamically efficient, but a heat pump for example can generate 3-4 kW of heat from 1 kW of power. The rest of the energy comes from the environment obviously, but naively assuming that the 100% efficient power-into-heat is the best you can do is not true.
Are there any efficient electric heating systems for a household based on a thermodynamic cycle with the environment?
I think the most electric heating systems I have seen are using the rather bruteforce and inefficient (only near 100%) method. The basic principle that they heat a resistor and something quickly transfers the heat away so the resistor doesn't burn out and/or your house doesn't catch on fire.
An other fun method to increase the "efficiency" of electric heating would be heating with bitcoin miners. It wouldn't make the heating more efficient in the sense it would cost the same energy but at least you could get some of your money back spent on heating.
I'm not quite sure what you mean your first question, but I think heat pumps using air, ground or water as heat reservoirs would qualify. They are in common household use at least where I am located, and have a input-power-to-heat efficiency of up to 400% (the Carnot cycle imposes a limit of roughly 7-10x depending on which exact scenario you calculate)
'Efficient' not in the thermodynamic sense, but in the sense that you need to put in x % less energy to have the same comfort level (i.e, have the house at a comfortable temperature at the times you need it).
And to add another use of 'efficient' to the mix, just to keep things interesting ;) , when people say 'heating a house with a CV (water) based system powered by natural gas is more efficient than using electricity', what they mean is that A) electricity is generated from other sources and there are losses in the conversion/transport/etc, whereas for gas that's not so; and B) that it's just much cheaper. So yeah, sorry for the confusion, but in energy use land, 'efficient' is a highly overloaded word.
Electric heating has near 100% efficiency regardless how you use it[0]. Heating with furnace is less efficient since some of the heat escapes through the chimney directly and efficiency is typically disproportional to the heating power so it's better to heat constantly[1].
In South Africa, most homes are built with little consideration of cold weather, since the winters are relatively mild. Problem is that draughts and poor insulation in winter then result in significant spiking energy usage.
Most houses have poor in insulation. Also, adding good insulation without degrading indoor air quality and causing moisture/mildew problems is tricky. So improving energy efficiency of heating for existing houses with lesser insulation is very useful.
My German apartment has drafty, unsealed wooden window frames, and the window in the kitchen is a single large sheet of glass. We have to hang a rug over that window in the winter, as it feels like you've left a freezer door open if you get within 3 feet of it.
I don't speak German so I cannot look it up, but my guess is these standards are for new buildings or buildings that are being renovated (and probably the numbers are different for private and commercial buildings as well, which is a shame), and owners of an existing building cannot be forced to adhere to the standard.
Thickness of walls is of course related to insulation, but it isn't everything; for example 20cm of typical insulation still has a much lower U-value then a concrete wall of 100cm thick.
It is a common complaint among people who moved from Finland to Germany, how dodgy the German houses are. If the rest of the world is even worse, maybe I should never leave home.
Hell, if you have good insulation, you don't really need any heating at all beyond that produced by cooking, lighting, and body heat of the occupants; except in really exceptional circumstances. You do need air exchange, preferably heat recovering.
Yeah, you'd probably need to spend over 1 million on a home here to get one with good insulation(if). Housing costs/quality is my biggest complaint for NZ.
This all depends on the type of heating system you have, the weather where you live, whether you have a humidifier on your heating system, and the insulation level of your house.
How much of this is thrown out the window when you have "peak pricing" for energy?
Also, the "straightdope" link doesn't exactly dispute that setting the thermostat down is ultimately a much more modest ~6% energy savings on average. Nothing to scoff at, but ultimately you come out better by taking a holistic approach. If you can afford it, of course.
Peak pricing isn't particularly common in residential power metering, though I suppose it might arrive.
The answer would depend on your heating/cooling cycle and usage. Most usage peaks are bimodal: early morning and early afternoon. Those would tend to correspond to morning and evening heating peaks, assuming your residence is largely uninhabited during the day. Overnight demand is usually low.
This could lead to, say, greater use of steam/water heating using thermal storage. Heating a well-insulated water storage tank with off-peak energy, then transferring that to the structure when it's most needed, would be a form of demand averaging / peak shifting. Depending on the storage methods used, boiler explosions might become an increased risk.
If you're using direct-delivery methods, e.g., radiant electric heat as described here, peak pricing would make some of the options used less beneficial on a cost basis.
I agree with all your theory. I thought the same thing. Then I went out and bought a programable thermostat, set it quite low overnight and during the day, and warmer from 5-8 AM and 5-8 PM. My heating bill was higher than just maintaining 68-70 all the time. And that's not even counting the $100 I spent on the thermostat (now on a shelf in the garage, I put the old manual one back in its place).
Either the laws of physics are different than well established theory says they are... or your thermostat didn't do a very good job. I vote for the second one.
Or there is more than one physical effect in play: see https://news.ycombinator.com/item?id=8112118 -- there's air movement as well as heat, because your house is not a sealed box.
Putting in heat over a short time, to recover from low temperatures, is different to putting in heat over an extended period. If your heater has very low efficiency at high heat output then it seems highly possible that extended low output could be better. It's a financial efficiency we're talking about primarily when people are looking to more efficiently heat their house.
If you're heating with electric for example you can sometimes buy electricity far cheaper at night (demand is low and traditional production can be easily spun-down). Thus buying electricity all night and keeping the house warm, whilst using more electricity, could be cheaper than paying for peak rate electric.
Physics alone could explain it in very rare circumstances - board construction that expands in warm air closing gaps, cool air opens gaps and causes more cooling. Heat exchange rate from in- to outside is then possibly greater at lower temperatures. Houses aren't simple to model.
Virtually all thermostat-controlled heating systems I've seen don't have different output levels, but are just on or off. So poor efficiency at high output wouldn't come into play.
The rest is possible, but I'd file using expensive electricity instead of cheap electricity under the thermostat not doing a very good job, or more precisely the person setting it up not doing a good job of setting it up to run more cheaply.
Gas fired combi boilers (with centrally heated [pumped] cycling water) are pretty much the default in the UK. I've never seen one that didn't have output temp adjustments. I'd imagine that set highest (which should reach thermostat set target temp fastest) would produce greatest flue losses but I'm speculating there.
I meant controlled by the thermostat. I'm sure you can adjust it manually, but in normal operation, it's cycling between on and off, and nothing more. Output level when heating your house from 50F to 70F is the same as heating your house from 69F to 70F, it just runs longer.
I'm sure there are exceptions to this somewhere, but it doesn't seem common. Thermostats don't typically have a way to command anything besides on and off.
From a thermal energy perspective this simply isn't possible.
However, some systems do lead to this because of flaws in the the implementation. My ground heat pump, for instance, has a backup electric heat system that it will automatically, and unavoidably, utilize if it hasn't reached the target temperature within a set, relatively short period of time. So in my very well insulated home I do indeed see significant cost increases if I do temperature setbacks, as the recovery period sees more expensive/less efficient electric heat kick in, versus just incrementally using the heat pump through the day. Some fuel-based systems go to a less efficient high-heat stage in the same sort of situation.
You are heating the walls and floors which take a long time to come up to temp. I liken it to the difference between keeping large truck at 65mph compared to getting it up to speed.
Looking at this as conventional power savings is wrong.
It's better to look at this as comfort. I just recently bought one of those 20 watt heat mats, for one specific reason: while using a computer it is impossible to keep my feet warm. Socks, boots, anything? Doesn't work. It was a huge problem while I was studying.
Since I got one, for 20 W, my feet are warm. In fact, my perception of room temperature as a whole has been massively improved. This is a lot less power usage then any type of whole room solution.
Well, not heating your house enough can also cost you your house as mold and ice can grow in very cold zone of your house. But I do like the ingenuity of the solution.
Shit Norwegians Say: “There’s no such thing as bad weather, only bad clothes”
>FAQ: It might work in Montana, but in Seattle, our windows would get moldy
>There are a variety of ways to mitigate the mold problems that occur in cold, humid climates. I did some experimenting when I lived in the Seattle area and have compared notes with people that are still living there. This is a really large issues even if you don't try this. While there are many things to be done, I think the first two would be: 1) learn how to properly clean mold problems (borax, not bleach) and 2) a dehumidifier nearly eliminates all mold problems and gives off heat.
That was one of the parts that made me go %O most - when you live in a house where the internal climate is such that it will let mold grow, it's downright unhealthy to live there. It's like saying 'yeah driving while drunk is dangerous, you'd better have a box of band aid laying around in your car for when you get into an accident'. Uh no, don't drive while drunk, eh?
> In addition, in 2004 the IOM found sufficient evidence to link exposure to damp indoor environments in general to upper respiratory tract symptoms, cough, and wheeze in otherwise healthy people and with asthma symptoms in people with asthma. The IOM also found limited or suggestive evidence linking exposure to damp indoor environments in general to shortness of breath, to respiratory illness in otherwise healthy children and to potential development of asthma in susceptible individuals. In 2009, the World Health Organization issued additional guidance, the WHO Guidelines for Indoor Air Quality: Dampness and Mould. Other recent studies have suggested a potential link of early mold exposure to development of asthma in some children, particularly among children who may be genetically susceptible to asthma development, and that selected interventions that improve housing conditions can reduce morbidity from asthma and respiratory allergies, but more research is needed in this regard.
Whether that counts as "downright unhealthy" is up to you.
It seems worth pointing out that the last 75% of the text you quote amounts to saying "we couldn't document these risks, but we'd like to warn you about them anyway". The first part links mold to (1) symptoms you'll recognize if you have them, in healthy people, and (2) asthma, in people with asthma. This is not a strong case for environmental mold being dangerous.
Vinegar is also excellent at combating mold (before it gets established), and is gentle on pretty much any surface.
A 50-50 vinegar-water solution can simply be sprayed onto walls, floors, carpets, and other surfaces.
Another is fully airing out a bathroom. I'll set a fan to move air until the walls and other surfaces are dry. Especially useful if you've got an interior bathroom. Otherwise, an openable window is highly useful.
No, though generally I'm not in environments where thermal control is a major concern, so the interior tends to be well-ventilated.
They key is to understand that a shower is essentially a big humidity generator. So you want to shower with internal doors closed, but external windows open, if they're available. Otherwise you're simply pumping moisture into the residence. Once you've completed your shower, you're no longer introducing more moisture into the environment, so removing / diluting what you've got is the key.
An exhaust fan is also useful, though most are relatively low-flow -- this is one element where if I am designing my own structure I'd have a high-capacity, high-flow, and if at all possible, quiet, fixture. A typical 100 CFM fan will require over 5 minutes to achieve a 100% exchange of air within even a modest-sized bathroom, say 6' x 12' x 7.5'. They'll rarely keep up with the generation of humidity during a shower. The real key is that a high-mounted fan removes the moist air that pools above your door jamb.
The situation also depends on whether you're in a warm or cold, heating, cooling, or ambient, and humid or dry environment.
In cold-weather winter climates, your usual problem is that interiors are too dry, so your bathroom humidity is useful for interior comfort.
In a temperate/warm and humid environment, your main concern is venting the bathroom (first) followed by reducing standing moisture. And if it's humid enough that interior humidity is an issue I've likely got a dehumidifier for high-humidity periods.
My usual strategy (yes, I've got a bathroom venting strategy) is:
For an exterior bath or one with an openable skylight: shower with interior doors closed and the window open. Humidity is generated by tends to escape, keeping total build-up limited. I may or may not shower with the exhaust fan on, but always turn it on afterward, if only to evacuate high-rising moisture. Following shower, spray down shower doors/curtain and walls with vinegar or other (preferably organic) anti-microbial. If the area has higher humidity, a 14" floor fan is good to help evaporate standing water on floors or walls. Mildew tends to form most aggressively in areas in which water pools, and by removing that water and treating it to be inhospitable, you'll virtually eliminate any build-up.
For an interior bath, shower with the interior door closed. Exhaust fan is either on or turned on following the shower (much more out of concern for noise than energy -- most fans I've encountered are annoyingly loud as well as relatively ineffective). I'll crack the interior door to allow fresh air in for a minute or so, then swing it wide open.
Swirling a towel can help achieve a good vertical air mix (moist, warm air tends to rise), which levels out total humidity and eliminates high-humidity spots.
Spray walls and floors with vinegar mix, finish my grooming, then turn on a floor fan to remove additional standing moisture on walls / floor. Airing out bath mats also helps markedly.
Note that a bathroom is rarely more than 10% of your total interior area as well (and often less). So even dumping a 100% humid bath's air into your residence will tend to provide less than a ~10% boost in interior humidity. My experience is that air tends not to feel overly humid until it gets above 60-70% humidity, and that humidity tends to normalize fairly quickly over a larger area. The real threat is _standing_ water.
End result is that I very, very rarely have bathroom mildew issues, rarely use a chlorine-based mildew treatment (though I've got a spray bottle of bleach too that may get used 1-4x monthly), and spend only a few seconds a day dealing with the matter.
Yes mold is very annoying, but maybe he can experiment with dehumidifiers in key areas to mitigate it. Of course it would probably kill a lot of his energy savings.
They are only very efficient in warm temperatures. The colder it gets the harder the dehumidifier has to work and the less efficient it gets - as it operates based on a temperature differential. So I suppose, if you are running a dehumidifier in a cold room, you need to particularly consider how well it operates in cold, some dehumidifiers are particularly bad in that environment.
Apparently he likes the light and thus the double usage (if you're already going to have a light on you might as well use its heat). I agree that the placement would drive me batty. Reptile heaters were mentioned towards the end and he uses them when having guests over.
Assuming you are not producing any EM radiation at frequencies that go through the skin of your house (radio, X-ray, visible light through the window, etc), any resistive heater will produce the same amount of heat.
Because guess what happens when EM radiation is adsorbed? It turns into heat. Any EM radiation.
I take a more middle-of-the-road philosophy in my house, with primary reliance on space heaters for room-by-room heating. Why do I care if the kitchen is 72°F at 2pm while I'm working at my desk in my office?
I live in Copenhagen, and it's also bizarro world for me. :) But mainly because electricity is very expensive here, whereas district heating (hot water produced by municipal plants, which you can draw through your radiator if you'd like) is quite cheap. It would be hard to beat the costs of district heating using a space-heater approach, even given better spatial concentration of the heat.
This is a wonderful benefit of living in a big city. E.g. Con Edison in New York supplies steam to commercial buildings.[1] Back when they generated electricity "locally" in each borough, the steam was almost free for them to generate as a side effect. But now they actually have to pipe steam under the East River.
But I no longer live in NYC. I don't miss the rats or cockroaches or traffic or air pollution. C'est la vie.
For many types of powerplants, a significant amount of heat is generated as a byproduct, sometimes even causing significant expense of cooling the plant on a large body of water, such as the nuclear plants near lakes.
That system can also be designed to provide hot water (both as a water supply and as heating) for a nearby city, and many cities do so, it's cheap and efficient.
Most large buildings in the parts of China that I've visited (4 different regions of the country) use government supplied central heating (hot water I think). Interestingly this supply is turned on in the fall based on local policy, which is often driven by economics and politics, So it's not uncommon for people to not get the heat turned on until much later in the year than anyone would really like... :)
Why are you at 74F? We're having a mini heat wave in Portland, so I've been running my AC. It's set for 76F and I'm quite comfortable.
You need to convince yourself that you'd be comfortable at higher temp and humidity. E.g. in Hawaii the "natives" sneer at the new arrivals who don't like the high humidity.
Fortunately this area has reasonably low humidity. But if I were in Florida, I could probably be comfortable at 78F as long as the AC got rid of about half the relative humidity.
Everyone is a bit different. If it's over 76 degrees in my house, I am mentally more sluggish, and have a very hard time sleeping. I don't mind sweating and being hot during the day, but at night I just can't sleep well. Also my computer gear has a tendency to overheat when things get much over 80 in the house at large (home office runs hotter).
Those 3 cold days every other year in Florida are pretty amazing. People wearing every warm piece of clothing they own, old sheets and towels flung over all the tropical plants outside, heat pumps running nearly 24x7 trying to pull a bit of heat out of the air.
Which is an excellent reminder that the challenge isn't heating or cooling, it's minimizing energy use as dictated by the requirements of your environment.
When I was a kid, we were rather poor. My parents scrounged together to buy a computer for the family, and I started to get interested in programming. But my parents were fearful I'd break their computer (not in a "don't be programmin'" way, but definitely in a "please be careful" way). And then a friend donated a computer to me. And I set it up in my bedroom. And I had my first comfortable winter in that house that year.
Of course, it made summers unbearable. But for the most part, I was used to heat.
I live in a larger house, being single any house is overkill but I went a bit beyond because of pricing and location. As such I have three bedrooms and two baths where the vents are kept closed. This does mean they seal completely so in winter the rooms can hit the 50s (F) on a below freezing week.
You don't need to live in a cold climate to want good insulation, it can save a bundle in hot climates too if your a fan of extreme AC; think 72F that some I know live by. I do the ceiling fan method, 78F and a nice big ceiling fan in every room.
An interesting approach - though for contrast, a well built passivhaus or low exergy design can achieve similar savings or even net positive. At a cost, true, but at much greater convenience. I feel having to do this is basically admitting that our houses are terribly engineered. And yes, with this kind of system you get problems with damp and mold which can have some pretty serious health impacts.
I don't know how people's desires can be "wasteful". I find that "summer inside the house" during winter is absolutely wonderful from the comfort standpoint and certainly wouldn't trade it for the saving that I would get on electric bill.
Of course, I realize that many people don't care for that. More power (and smaller bills) to them.
> I don't know how people's desires can be "wasteful".
In a world where people paid for the true cost of their energy use, this argument might fly. But in most of the world today, this isn't the case, not by a long shot.
If you heated to "summer inside the house" and bought high-quality carbon offsets corresponding to your increased energy use, I think most people wouldn't call that "wasteful". "Warm" might be the adjective I'd use. :)
In a world where people paid the true cost of their energy usage, there wouldn't be an absolute deluge of houses built by terrible contractors with terrible insulation on the market, where the biggest, best and cheapest energy saving measures weren't put in when the house was built.
I want summer in my house during the winter. This should be an explicit goal, because you can't get there by just cranking up the heat since it doesn't deal with draughts and the like. If this were a recognized goal, then everyone would be better off in every way.
The cost of carbon offsets is apparently less than a penny per kWh. This is barely anything in comparison to the price of the electricity itself, so it doesn't matter whether people are in actuality paying the true cost; they might as well be. Such a world would look almost identical to our own.
I couldn't believe this, so I checked around a bit.
According to [1], the cost for offsets are $5.50 to $29 per ton of CO2. According to [2], 1 kWh produces 2.08-2.18 lbs kg of CO2 when burning coal (0.94-0.99 kg). Thus, the cost for the offset is about 0.52-2.9 US cents/kWh, or when using different power sources[3], 0.32-1.7 US cents/kWh, hence your number is about right.
Now I guess the next thing to check is how solid those offset efforts really are. Also, probably they are cheap because they are the low-hanging fruits, I suspect that if everyone would offset their usage, the offset costs per kWh would become much higher. Thus, your assertion that the world would look almost identical if everyone would pay the true cost may well still be wrong.
Even if you're doing a couple hours of intense exercise every day, you're only going to be adding on the order of 1000 Calories to your daily usage. Resting burn for most adults is around 1500-2000, so that's ~3000. What do you consider "sufficient" exercise?
It may be wasteful, but that's what I want. I don't ever want to step out of the shower in the morning and shiver again, I find this deeply unpleasant. I also don't want to have to wear thick woollen clothes around the house. In pursuit of this I actually moved to Australia for a while, but it turns out I missed the temperate climate and UK culture (also my family, I guess...)
So when I own my own home in a few weeks it will be getting insulated to hell and back. Eliminating drafts, insulating attic space, replacing some of the old windows with double or triple glazed ones, checking the state of the wall insulation... etc etc.
But when it comes down to it, I'll pay the heating costs and swan around in my t-shirt all year. I like being warm.
But yeah, improving isolation, having a bathroom heater, using heat pumps instead of electrical heaters are better than just cranking up the heat and paying the bill.
Imagine a radiator you turn on for those few minutes. Could probably keep you warm using a lot less energy than it would take to heat the bathroom air and walls.
But you can't power a computer on PV. I don't think anyone who knows something about energy efficient heating suggests PV to warm a house electrically, it's too inefficient.
Not my comment you're responding to, but it's not talking about PV for heating (that'd be kind of ridiculous, honestly).
Systems for heating water/air using solar can be quite inexpensive as well; converting light to heat is rather easier than converting it to electricity.
E.g., I've seen cheap pool-heating systems that just pump the water through wide flattened black pipes exposed to the sun and send it back into the pool. Voila, solar heating!
Yeah my second sentence was a non sequitur, but my point was: you can only do a little with solar/water heating. Yes heating a pool is one of those things, but that's a very niche application. This thread is about heating a house, or at least about being comfortable in one, and solar/water is just not a viable technology for that in the vast majority of cases.
Oh... you said "PV" in both sentences, which is specifically converting light to electricity; that's what threw me.
For heating a house with solar (not PV) -- it would depend on insulation level, I'd imagine. I do know people who use it for "most of the time" water heating, with good results.
>In June of 2010 I moved to a place in Montana with only electric heat.
Living that far north and depending on one heat source is crazy! Think about the power going out when its -30 out... or if you used gas, running out or having your furnace break down.
(Not to mention electric is usually the most expensive way to heat). Most houses where I live have 2 or 3 heat sources. I have wood, LP and electric...
I live in the northernmost large city in Canada (where we get -40C pretty regularly for a while in the winter) and every apartment I've ever lived in has only one heat source, and usually it's either electric or water pipe.
If your power goes out long enough for all the heat to leach out of your apartment or house you probably have some serious problems with either the electric company or your insulation.
Heh, last Christmas the power was out for about two weeks at my parents' house, which uses electricity to push the hot air generated by our gas furnace through the house. It was -25 C.
Granted, I might not have had to go to the hospital if we had gone to a warming shelter earlier than the sixth day. (My father is rather stubborn, and it damn near killed me. When I got out of the hospital, I left the house and paid for a hotel room in a part of town where power had been restored.)
I lived in Minnesota and had only electric heat. Most other houses have only gas heat, and it usually requires electricity to run. Luckily the electricity is pretty reliable.
If you do lose heat, the solution is generally to use blankets outdoor gear until it is fixed. But this has never happened in my 20 or so years of living there.
A similar approach works in hot climates. A friend of mine saved a substantial amount of money by getting an efficient portable AC unit for his bedroom, and shutting off the main air conditioner for the house at night. In a southern summer, the savings add up quick.
Portable AC units are highly inefficient when compared to large fixed units. If you only want to cool a single room the best solution is probably a mini split. They're expensive but very efficient.
Depends where you live--a house with no air conditioning generally won't suffer mold, and neither will one with air conditioning. But spotty air conditioning without something like a dehumidifier will breed mold and warp floors.
A friend of mine has been complaining about his rental's warped kitchen floor and mold (or the fact that mold forms easily). His windows are mostly painted shut. Can you elaborate on this? What kind of a dehumidifier should he look at?
I have a portable air conditioner but it is not as portable as you would think. It is about 2.5 feet tall, sits on nice rolling wheels and has a small exhaust and fitting so you open your window and put the pipe end in place to vent the heat. You do not have to mount it in the window which makes it portable. I can move it from room to room and it only takes about 2 minutes to setup the fitting.
This reminds me a little bit of a company I've visited.
They cooled the office so much in the summer that some of the people in the office (I'd say 5 out of 20) used electric heaters under their desk to warm their feet.
Unfortunately even a cheap table in the U.S. is more expensive than it should be. There's an opportunity for someone to create kotatsu tables and things like them for the American market.
Very much the "philosophy" of heating here in Japan; heaters for single room, heavy futons on the bed with no heater, kotatsu, foot warmers, etc.
Comes from old, leaky wooden houses, but idea is the same. Lot of bad habits here still, but heating the upstairs guest bedroom all winter long isn't one of them
Given that he uses electric heating, it's pretty funny the electric company wanted him to switch to florescent. That buys you nothing in those months where the heater is on.
What I'd really like to know is: why not switch to gas?
He mentions homesteading at the end. I guess he doesn't have a natural gas supply available. Propane and fuel oil aren't the completely obvious win over electric that natural gas is.
I'm talking about utility supplied natural gas vs truck delivered liquid propane in the U.S. I'm pretty sure the natural gas is consistently cheaper (frequently to the tune of 50%, my experience of it is in northern areas where the propane trucks are busy all winter).
This is why changing out incandescents for CFL's in a heated house does almost nothing for saving energy... and if the heat comes from electricity, nothing for saving money, either.
- for half the year, you don't heat but you still light, so you automatically gain savings for that whole period. (also if you have air conditioning, in summer you heat the house with lights then have to cool the air again)
- Lights are on the ceiling. Hot air rises. Therefore heat coming from lights does almost nothing to improve your thermal comfort.
- If you are heating using gas rather than electricity, it is far more efficient to heat air with energy from the gas boiler than from the electric lighting
What's the energy cost of making a CFL bulb vs. an incandescent? Also since in practice they don't last a lot longer, and are annoyingly dim for the first few minutes, and are considered an hazardous waste when you need to dispose of them, why does it make sense to replace a $0.50 bulb that has none of those issues with a $5.00 bulb that does?
Not sure what you are doing to your CFLs to make them not last longer than incandescent bulbs. I think i've had maybe one CFL break, and that was an early model. LEDs are of course much much more reliable and will most likely outlive you, though personally I don't like this obsession with trying to cram them into traditional light socket formats - I'd like to see something a bit more innovative. They work particularly well as spotlight replacements and ikea have a nice range of innovative designs that don't cram the LEDs too close (which causes heat buildup and reduces efficiency).
CFL is crap, use LED lights. Last 20x longer with 1/20th the energy use. Replacing incandescent with CFL is a wash, replacing them with LED is a no-brainer.
You can get LED lights in a variety of color temperatures. You can even get ones like my Phillips Hue bulbs whose color can be adjusted remotely. They aren't cheap but they're a lot of fun!
For sure. I just meant that if you prefer bluer light, you can get that with CFLs, but they can't give you the 'softer' light that we're used to from incandescents, while LEDs can (if that's your preference).
This is likely mitigated somewhat if you have good natural light sources. The warmer it is, the less you need to run artificial lights (assuming a "normal" sleep schedule.)
I wish whoever downvoted this would indicate what part of my comment they disagree with... I said "If A then B", and then the response was "wrong, because if not A then C".
Of course it saves energy if you don't heat the house, that's obvious. What's less obvious to many is that it saves much less than you think if you live in a house in Northern Sweden, heated with electric heat (which I happened to grow up in).
Of course it does. Heating up a hole in your ceiling does not efficiently warm the occupant. You want to introduce heat low and near occupants.
Also, changing out multiple incandescents means more manufacturing, more truck deliveries to the store, more manufacturing, etc. vs. using a single LED bulb for two decades.
If you live in coal country, then you definitely want to reduce your electrical load and instead rely on a less-bad option of natural gas for warmth.
Most heat from incandescents is infrared radiation, which travels. If you get useful light from the bulb, you also get useful heat. Plenty of rooms are heated with one big, honking radiator, which certainly is no more effective.
That said, it's true that some of the heat ends up not being useful (just like a lot of the light from the bulb doesn't either) -- unless there's a heated story above, of course.
And I never implied that I think it's a bad idea to get rid of incandescents, for all the other reasons you mention.
Manufacturing and shipping costs of incandescents are very small relative to their energy utilization, as reflected in costs.
Your point about fixtures and heat losses through ceilings are actually well-taken. Recessed "can" lighting is actually a huge pathway for heat loss two ways:
1. The radiant heat from bulbs which is transferred into the ceiling and attic spaces, rather than the living space.
2. Other heat flow losses, including often very significant airflow, through the lighting fixtures. Thorsten Chlupp (mentioned elsewhere) includes lighting fixtures among his anti-penetration measures. He also keeps his wiring and plumbing runways along the inner insulates spaces, rather than outside the thermal barrier (with concomitant envelope penetrations).
The el cheapo ones, yes. There are expected lifetimes on LED bulbs ranging from 2000 (similar to incandescent) to 50000 hours. Of course the 50k ones are (much) more expensive.
During heating season you are correct. During cooling season you end up paying twice for the extra energy consumption of incandescents. So it ends up being climate dependent. In cold countries the savings from changing out incandescents can be a fraction of the savings obtained in hot countries. Where I live you only end up getting half the benefit you would expect from the energy savings alone. If you don't have AC here then the benefit is even lower.
There is a current internet legend that the heat from incandescent bulbs does not contribute significantly to building heating. This is entirely wrong for the obvious thermodynamic reason. It's even been tested experimentally with the result that almost all the heat from the bulbs ends up as general heating:
Three ladies at my company campaigned heavily for those heated keyboards a few years ago. One shorted out within the first month and the other two stopped functioning within a year.
Then you use insulation. This especially is something that feels nobody in the US has heard of. At least in California.
As a result, your radiators are turned down to 2 out of 10 all day (heating turns off automatically overnight), and you have to sometimes open a window when it's -13C outside so you don't sweat.
Now I don't know how much people spend on heating when they live in a house house, but my apartment's heating bill this winter was about 30 euro a month[2] and I had to keep all my radiators turned off because the one in the bathroom couldn't be regulated. So that alone was enough to heat everything to extremely comfortable levels.
tl;dr don't heat with air, insulate your fucking house, and install modern windows
[1] Could just be where I'm from, but it seems fairly common in Europe and not at all something I've seen in the US
[2] I think my gramps spends about 2k euro in October to pay for natural gas that heats his house until some time in April. So about 300/month for a ~10 bedroom house because he's got a house that's way too big.