We had one growing up in Iowa. Despite upper 70's to mid 80's much of May, June, and July, we were able to avoid running the air conditioner by sucking in the 50-60 degree air overnight and closing up the windows during the day. By late July and August, it was time to use the air conditioner.
The fans can typically rotate all the air in a house every handful of minutes, and the breeze helps sweat evaporate, immensely helping comfort. Their cost is typically a couple hundred dollars, but you can spend up to ~1,200 for a quiet, high volume model.
I'm looking to install one in my house. The downside I'm trying to work through is, should a fire break out, I want the fan to turn off. I haven't found a COTS system to do this and integrate with the hardwired smoke detectors.
Last time I noticed, nobody makes a window-sized AC-esque filter that works efficiently down to PM2.5 levels... and doing so would also eliminate said window being a window.
My dad was ahead of his time. He installed a geothermal heat pump to heat the house with heat from our 200’ well, too.
Thanks for a pleasant reminder!
Fires spread much faster than they used to because of changes in building materials . I figure if I can find a way to shut it off automatically, it'll buy me 30+ seconds, which is a big deal.
I found  awhile back, which is what I want, but I'd happily pay for a COTS solution.
Plus, how many residences (other than chic converted factory lofts I guess) even have bare brick and mortar interiors?
And, depending on whether your fan is in spec for the built in relay, you may need a larger relay to switch it.
My dad spent a few years thinking through details about the house before building. Passive radon mitigation was built in (active added later), air exchanger would bring in new air without losing all the heat/cold of the conditioned air, radiant floor heating in the basement, ~24" of blown in insulation in the attic, 6" walls for additional insulation, 24" eves give a bit more shade around the house.
When we installed the fan, the documentation mentioned failure to open 9 square feet or more of outside doors/windows could result in a window breaking from the negative pressure.
A negative pressure house is bad for more than just radon. It can cause certain appliances to vent bad stuff into the house too.
Separately, offgassing is an issue for sofas and mattresses, anything made of particle board as well, but if you put them in a low pressure environment, it doesn't drastically accelerate offgassing. If they offgas formaldehyde, they're going to keep doing it after the low pressure period has ended, so better to avoid those materials altogether.
After mapping out my house we saw numbers as high as 15, 4.0 is the recommended mitigation threshold in the USA, 2.6 for the EU.
After talking to a company they recommended sealing our sump pump area, and then installing a fan that sucked air from under our foundation. Our readings dropped from 15 to 0.5, and stayed there. I do wonder how long the sump pump sealant will last, but I have the airthings to watch.
So sure, open up the windows when you can, but I'm glad I can close the windows when it's smokey or cold and still have low radon levels.
Please don't spread this anti-environmental claptrap. Expending energy does not "heat the planet", as a quick consideration of the night side of Mercury would reveal. It's greenhouse gases in the atmosphere that heat the planet, and they'd do so even if humanity vanished tomorrow. To the extent that "energy consumption" is at all related it's purely in terms of externalities in energy generation, but we have the tools to deal with those.
There has long been this strain of moral Puritanism in environmentalist movements wherein people must suffer and "return to nature" and such to be Green. But more often then not no, we don't. So I consider that to be an anti-environmental, counterproductive stance since it creates a false choice wherein people are told everyone must give up often key parts of their lives entirely or else they're bad. Given that, it's not surprising many will plump for the status quo. But in reality it's completely fine from an environmental point of view for everyone to spend their luxury energy budget as they wish, and indeed gaining/growing that is a key bit of human progress. What needs to be done is ensure that energy budget, unlike today, is actually environmentally (and in particular GHG) neutral. Societies can work from there.
On the other side, and especially here on HN and the like, the tech building, win-win seeking, prosperity maximalist “Wizards” essentially just keep trying to build their way out of problems, e.g. massive gains in ag productivity of pesticide treated, fossil fuel fertilized, genetically modified high yielding, mono cropped strains that have already saved a billion.
Cannot recommend “The Wizard and the Prophet” enough, a great history of environmentalism in the 20th century and how this split evolved, and it’s not nearly as biased as I am (though still clearly leaning “Wizard” in its text).
While you're not always wrong to say that expending energy doesn't have to heat the planet, it's wrong in practice for the substantial percentage of the world where energy production emits greenhouse gases. Until that percentage is zero, there is a considerable amount of good which can be done by using less energy and we have enormous efficiency wins possible without any real suffering.
As a simple example, a geothermal heat pump system will require less power than a convention gas heater and AC system even if your thermostat is set to the exact same levels. A building which is designed with passive cooling (heavy earth walls, use of ground/water cooling) or windows placed to optimize for winter sun angles but not summer will require less power to maintain a comfortable temperature. As long as your power is not completely emission free, that's probably a win — and if you are trying to fit within the solar/wind/etc. power you can generate on-site the lower usage will make that easier.
I also think just doing things like living more spartan can help but I don't know how to sell people on that idea.
Thankfully, they got lucky and built right next to a trillion dollar company's headquarters, so they will still be able to sell at a premium.
It got hot.
I went to YouTube and found a few videos -- I had already known about the two fuses leading to the A/C unit, mine were fine. I hadn't known about a capacitor that was used to assist the fan in starting and discovered that taking a stick off the ground, starting the A/C and whacking the fan was enough to make it run. I ordered the replacement from Amazon.
I had forgotten to cancel my appointment and the gentleman with the company arrived mid-morning. Being that the unit was all of 5 years old, and I had a good understanding what was wrong, I wondered what I'd be told so I acted dumb. Wouldn't you know it? It turns out that "the compressor is no good", and that "the kind of compressor used in this isn't made any longer". I told him, "Ah, that's too bad, I guess I'll have to have my Dad come out and replace it" and sent him on his way. Two days later I installed the first of the two capacitors I purchased and had working A/C until early this summer. This time when it failed, I took the panel off, saw the cap was bulging, and replaced it. Fixed. For those keeping score, that's 10 years on an A/C unit that apparently had a bad compressor and required replacement 5 years ago.
The moral of the story is that a few minutes of time on YouTube can save a lot of money and literal sweat. If you have a professional that you trust, great -- if you don't, get a second opinion before dropping a large amount of money simply because the A/C repair company sent a sales-person out when what was needed was a technician.
 It wouldn't start on its own, but I could get the house down a few degrees below comfortable and leave it off for the night, at least.
 I called a few places the following morning and nobody carried capacitors that size, locally; Amazon was it for guaranteed 2-day shipping; I miss Prime. It also appears my capacitor isn't affected by the parts shortage -- there's several on EBay and Amazon at present.
 The technician (who was actually a sales-person) attempted to mix up energy efficiency standards and actual coolant formulations; I don't recall exactly what he said but I recall searching the finer points and discovering that I had a very high-end A/C unit, and the entire compressor was available in used/new forms. Oh, and mine is still "just fine".
I would not try this at home.
I have only worked with a motor start capacitor in the context of mine and a few neighbor's A/C units. Anything I do is small circuits, DC, and not a mess at that. Frankly, the look of the thing upon removal made me fearful that nothing about what this thing is supposed to do could be trusted (large bulges on both sides).
I've worked with others of about this size, and smoked some hair on my arm with one fully removed from a Mitsubishi rear projection television (with an actual hole in what probably constituted its main board) from somewhere in the early 90s. It's the only time I've held onto a disconnected component "just right" to get a surprise and I'm not certain I touched more than hair. It didn't have anything but 400V written on it, no idea what purpose it served, honestly yanked it "because I didn't have one" and I'd never seen one that large up to that point. And I never found a use for it; it's probably still sitting in my battery box in the basement :).
Bottom line: the AC unit service door, and several other places around the unit, and within its service manual have affixed, sometimes etched, warning labels. At least some of those were added after someone died. It's worth a good read and a little bit of caution.
Please don't accuse others of spreading FUD when this type of repair is legitimately dangerous.
Edit: There might also be other bits in the system with residual power that refill the capacitor even after unplugging the mains, so a voltmeter is a good idea as well.
Shorting a starter cap won't do anything of what you said. These caps are actually small (couple hundred uF). At the worst you'll produce a small spark. nothing more.
Like what, when it was already turned off? And especially, what do you imagine recharging a significant capacitor to more than 50 volts?
Wear (rubber) gloves, short circuit anything you're going to touch with an insulated screwdriver, and you'll be fine.
A new capacitor is about $20 vs. $250+ for any service visit.
I mean sure as anything they can throw you back into your seat and cause a relatively decent burn but in practice are they really an electrocution risk?
You're not going to get trapped and unable to let go.
Looks like the biggest risk from a high voltage DC discharge is myocardial depolarization, and that's dependent on the current path and the timing of the heart rythym, but that's typically at energies an order of magnitude more than a charged typical motor capacitor
An AC motor capacitor would probably just give you a short shock since it's only used to introduce a phase shift on the auxiliary phase in single phase AC motors (what the OP is talking about) or for power factor correction in 2/3 phase AC motors. AC switches every 20 ms from positive to negative so the cap only stores very little power. I'd be more weary of capacitors in DC circuits.
If you've been "bit" by a small cap on a circuit board, imagine one as big as an adult's fist. I don't recall the output of this thing but one needn't read the label to know that if I can't completely enclose this thing in my hands, it's probably not something one should...enclose in ones hands? It is also in a nice metal container that's probably under more pressure than it should be; mine were always bulging.
With board mounted caps, a lot of this stuff lands in the "leaving pizza out overnight" category. I've only had one (small one) truly explode due to age/being defective; several that I blew up in electronics class when the teacher's head was turned, but hey. And about a flobbidy-gillion that bulge, you could lick the leads (that's sarcasm, don't actually do this).
Now, fan caps/mostors like this -- I've been bit by (a 400V cap that was "not dead yet") -- I don't know that I actually touched the leads so much as some hair on my exposed arm made contact (it's why I wear my long welding gloves!). ...There's that moment well after you've registered the burning sensation and smelled the hair that you say a prayer of thanks to God while panicking that the business end is not yet any safer than it was a second ago.
The (somewhat unsafe) procedure I used was: Cut the power, pop the fuses, pulled the wires in the order I had in my notes from last time (with thick welding gloves), pre-cut electrical tape to cover the three leads (model has lots of distance, it's a big cap). The cap is connected by three wires, far from the rest of the electronics, easy to get to, easy to remove/re-secure the wiring, admittedly -- easy to get a little too comfortable.
Carefully handle those leads; hopefully goes without saying -- even if the cap isn't bulging -- avoid heat-based treatments (hot glues/heat shrink). I tape the hell out of the big ones. I've only had to personally handle a small number of these, but there's a TV repair shop in the area that does free electronics recycling. I told the puzzled 15 year old at the counter what it was, he looked puzzled, so I explained that it can explode like a hover-board battery and he shrugged. I guess...good enough.
 In a manner that might have been a fire hazard, and were it exposed, could have taken an eye out. In my case, a moderate "pop", a black spot on the board, smoke, and shrapnel throughout the small case.
I take into account the typical audience of the site, though. Most of us tinker/work with highly complex things that require good research skills even if they don't touch electronics. The basics of how a fan capacitor works, how to handle one safely -- including testing, and discharging, can be done for less than $100 in parts including the required resistor/multi-meter -- in my case. But after inspection and planning, I opted for skipping some precautions and relying on "being careful" which I don't recommend, but how many deaths is that, really, if we all try it? (/sarcasm)
In the case of my unit, there was maybe three seconds where -- if a reasonable enough charge were present (and I had every reason to believe it held enough to hurt ... a lot ... which is motivation enough) -- I was in danger of receiving it if started pouring on me spontaneously on a clear day -- I didn't have remove the cap from the unit to secure the leads. I suspect a lot of A/C units are similar, but YMMV and I'd be willing to bet, again, most readers of this site possess the wisdom to judge the danger for themselves after suitable reading/watching.
 Common sense which starts with Rule #1: Always have a physical witness if you're working on something that can kill you and ends with #2: Use them to double-check your research if it isn't obvious stuff (or my personal favorite, have them handle the dangerous stuff).
The other thing he drills is to change. your. filters. Buy a box of them, put it next to the air handler. Not doing this during spring and fall will kill your central air. It screws up the careful balance of pressures and temperatures that your installer had to establish. Eventually your evaporator or condenser blows a hole and vents itself… which will probably kill your condenser too. Five minutes of effort, twice a year and you can add years to your system’s life.
If you want to filter air, buy a separate air filter, and let the air handler just handle heating and cooling (if that is what it is designed for).
If you have an excessive pressure drop across the filter you'll have slightly lower airflow across the D/X coil which results in less energy extracted per second the compressor's running.
That doesn't "strain the system" in any straightforward way. It's going to increase your compressor runtime, yes, and the delta between your return and discharge temperatures will be less. (The discharge won't feel as cold)
Mostly excess pressure drop is caused by dirty filters. A clean MERV won't drop the pressure low enough to result in the D/X icing up so you're still cooling.
Depending on your local thermal load, especially in shoulder season (spring, fall) slightly lower airflow might even improve your system's lifetime because it might reduce short-cycling. Every cooling cycle counts towards eventual failure. That's going to depend on your controller, though.
Working out the details for your system is an involved engineering exercise. A field tech telling you "MERVs are no good" isn't doing that mental work.
A MERV will get dirty and saturate faster so if you're using MERVs you need to change them more often. A saturated filter will slow air enough to ice the coil and then you have a real problem.
All that said... if you want very clean air, buy a box fan or squirrel fan and tape a MERV filter to it. Squirrel fans deal with this better but the shape's less convenient. Stick it in a forgotten corner.
Don't buy a stand-alone commercial air filtration device. They're a total rip-off.
It’s kind of like how (traditional) circuit breakers are designed to protect the premises wiring from catching fire when too much current passes through them. They could care less if you get electrocuted or you overload a higher-gauge extension cord (GFCI and arc-fault are another story though).
In school I was demonstrating a little rail gun powered by one of those caps. When done, I went to take a seat.
Upon sitting, I placed my hand on top of the capacitor, and no joke the muscle spasm shot me up so that I was standing again.
Mind you, since then I've gotten some more expensive screens, I have one from Dell that's been going daily for ten years now and is still fine.
So far I've found this applies to legal services, automotive work & health services as well.
I've had pros quote me $600-700 for the repair when they thought they had me in a tight spot, and I already knew it was a cheap fix.
Burt even reputable AC guys are going to charge $100-200 for replacing capacitors.
It's a five minute fix one you know how to do it safely.
Also: if you have a noisy/ whirring compressor, the capacitor is likely the source. Either it's going out, or the last guy put in the wrong size capacitor (because he didn't have the correct one already on the truck).
It's actually not at all dissimilar to how many things in computers work.
Toyota, which pioneered lean manufacturing, is currently laughing its way to the bank; it has a stockpile of semiconductors, since the 2011 Tohoku quake and tsunami exposed how fragile its supply chain for semiconductors was.
If it makes sense to stockpile for the company that pretty much invented lean manufacturing as we know it, it's not without merit.
Sometimes you want the talent close. Sometimes you want critical parts close. Sometimes you want your neighbor to have a job.
Until there's a working Basic Income; I prefer keeping most jobs/products close.
As for programming jobs, I think most people who have been in the field for a while have seen plenty of examples of how offshoring doesn't work, and from what I've seen this is known in the c suite as well.
Here, have a read: http://archive.kuow.org/post/modern-seattle-building-doesn-t...
AC cooling has massive advantages, there are solid reasons why every building should have heat pumps. Doing some of these techniques can reduce the load on HVAC systems, but eliminating them entirely is a bit silly.
What's silly is the fixed working time and not allowing and training our bodies and ourselves to accommodate the temperature. There's a reason for siesta, and a reason for Mediterranean people being active at night.
I went to the WalMart by my house, today, to replace a blender who's motor failed. I realized as I passed the bike section, now 1/8th full, that "hey, (awful) bikes are back!". They're not, but there were a whole ten of them which is ten more than I've seen all year.
Hop over to the blenders and they have fifteen models on display but boxes for 5 of them.
Only self-service check-out is open, and only half of them, the line extends ten people past the "impulse buys" in the six "any number of items" self-checkout lanes. Two members of front-end staff look like they're ready to burn the place down, customers have stopped swearing under their breath and are now engaged in outright, obvious, complaining. I roll up to the chaos with my less-than-desired blender and realize I might as well just wait for shipping because it's 10:00 PM, this is an hour long line, and I'm not going to be the reason these poor employees have to stay late since the 24-hour WalMart hasn't been open past 11:00 PM since last year.
It's a lot of griping, and I'm really not upset -- I got a nice excuse to hop on my one-wheel in the dark and avoided spending some money on something I don't need "today"; a really minor inconvenience, I just miss the good old days of ... 2019? :)
As an example, I heard there’s a 1,000,000 unit backorder of market-leader Bosch’s dishwashers.
Where there are delays, they aren't necessarily “a few days” but months, and, yeah, life in, say, California's Central Valley in a hot, dry summer without AC is somewhere between unpleasant and intolerable.
I live in Michigan -- about once every 7 years we get unseasonably warm summers. It's been 85-95 degrees through June with the sort of humidity that makes it feel like you have to actively think about breathing.
People die from heatwaves; modern conveniences like A/C make that sort of thing a lot less common these days, so while the original comment writer's attitude that "modern life is no longer possible" may have been meant to poke fun at "first world problems" -- yeah, I get it, we all have it pretty good -- these "conveniences" do more than just "make quality of life a little better".
 Not saying there aren't downsides, either, but I'm not willing to give up my A/C for 'em.
We visited the UK in late May during one of those heat waves and got stuck on the London Underground in a very hot train. Lots of fun!
Also, this isn't just about cooling; it's about heating, too. Imagine living in Saskatoon SK without a working heat source. Nobody does that. If you're not relying on electric/gas heat in such places, you're relying on fire.
Nearer to the equator pretty consistently means less seasonal variation in temperature, it does not mean higher summer peak temperatures.
Lee Kuan Yew, founder of modern Singapore: "Air conditioning was a most important invention for us, perhaps one of the signal inventions of history. It changed the nature of civilization by making development possible in the tropics. Without air conditioning you can work only in the cool early-morning hours or at dusk. The first thing I did upon becoming prime minister was to install air conditioners in buildings where the civil service worked. This was key to public efficiency."
AFAIK; the pieces where lots of people tend to die from heat waves in are the places where there isn't a regular annual need for AC.
There are greater economic threats pushing people into these skills.
Personally, since I have them, I am happy to share with others during these times. Just good to know. And one never really can know when it all will matter.
Either way and in any case it is worthwhile learning what is being done, even if only to make sure corners aren’t being cut.
It's typical if this is the rule for a tradesman to refuse to sign off on work, or charge you a high fee to do so.
In any case, it means "you can do it yourself but..." is pointless.
Getting major work done without a license seems like a great idea until one tries to file a major claim with their homeowner’s insurance.