
Simple Techniques for Lowering the Cost of Zero-Energy Homes - catawbasam
http://www.greenbuildingadvisor.com/blogs/dept/guest-blogs/simple-techniques-lowering-cost-zero-energy-homes
======
dmm
There are so many simple things we can do to make more energy efficient homes
but builders and buyers don't care. They will happily spend thousands on dumb
things that are highly visible but won't spend a few hundred on something as
simple as sealing ducts so 30% of your conditioned air isn't lost.

A carbon tax would go a long way to solving this by giving people correct
price information so they can make good decisions. If energy was more
expensive people would demand more energy efficient homes.

~~~
ballenf
I'd rather see something like nutrition labels but instead efficiency measures
in various areas for new homes before a tax.

Having bought a number of homes it's surprisingly painful and infeasible to
compare apples-to-apples upfront. "Easy" to get details on a per-house level
but just about impossible to filter your search early based on efficiency.

~~~
pcardoso
This is already a thing at least here in Portugal. This is a energy efficiency
certificate that is now mandatory when renting and selling a house:

[http://www.adene.pt/sites/default/files/documentos/certifica...](http://www.adene.pt/sites/default/files/documentos/certificado_adene_reh.v2.pdf)
(PDF)

~~~
ptaipale
All of EU, but in my opinion it's mostly a scam.

Companies that perform this certification lobbied to make it mandatory
whenever selling a house. However, the certificate does not tell you the real
energy consumption. The calculation is based on "weighting factors" for
whatever energy production format the politicians want to favor currently, so
at least where I live, in Finland - where energy consumption really matters in
the winter - when you buy a house, you pay for a certificate that is not very
useful, and then you ask the previous owner for the actual energy bills he
had, to asses the real cost and consumption.

The latter is, of course, what everyone did already before this certificate
system.

OK, it's just a few hundred euros per sale. A bigger problem in the various
energy saving initiatives is that houses built to this code sometimes develop
very nasty air quality problems (due to air not changing in some places fast
enough, or subtle leakages in the airtight balloon where you live) which then
forces costly renovations and in the worst case destroy health.

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ZeroGravitas
I'm amazed that society level efficiencies like these aren't considered a
bigger deal.

If people are burning more gas than they need to that's less money for them to
spend on everything else. It's like the whole country living on credit card
debt and not worrying about the interest because it's in the future. It's
making you literally poorer and giving you nothing in return, just due to a
lack of foresight and planning.

~~~
jaclaz
>If people are burning more gas than they need to that's less money for them
to spend on everything else. It's like the whole country living on credit card
debt and not worrying about the interest because it's in the future. It's
making you literally poorer and giving you nothing in return, just due to a
lack of foresight and planning.

Only it doesn't work that way.

The deal with the builder has traditionally been (only an example):

1) you pay upfront US$ 40,000 _more_ for the construction of the house in an
energy efficient manner

2) we promise you that this will allow you to save US$ 3,000 per year in
energy

3) for whatever reasons the savings actualy result in US$ 2,000 per year
instead, but that is "normal" and within the expected calculation error, and
anyway we already got the additional US$ 40,000, sue us.

4) part of the added US$ 40,000 go in part (heating, cooling, ventilation,
windows) that require some added maintenance costs and that won't anyway last
20 years and/or will have higher replacement costs.

5) also consider how the "savings" are dependent on actually living in the
house, if you - say - go six months away closing the house, you won't spend
anything for energy, while you will be paying anyway the added US$ 40,000 on
your mortgage payment, same thing if you rent it, the people living in the
house will get the savings, you will still be paying the same.

~~~
kevstev
1- I am not sure what kind of house you are talking about, but typical costs
for energy efficiency result in less than a 10% increase in total costs.

2- ok.

3- The savings can be much greater than that. Insulation alone has an amazing
bang for the buck. And its passive.

4- Added maintenance for windows? They don't require a diamond polisher to be
cleaned. Who replaces their windows and doors every 20 years? What
specifically needs extra maintenance?

5- Even if you are not living in the house, you can capture a higher profit
margin by including utilities in the rental price, or marketing it as an
energy efficient house. This is a real edge case though. Interest rates are
about 3.5% now. Even in your inflated cost estimate, that translates to $700
in interest for 6 months. Not exactly game changing IMHO.

You are also missing an important point- energy efficient houses also tend to
be a lot more comfortable, there are less drafts, less swings in temperature,
less affected by outside noise. And you get the satisfaction of not having to
care so much if energy prices increase.

~~~
ashark
> Who replaces their windows and doors every 20 years?

Do modern windows even last that long? From observation of my own and
relatives' houses, and from looking at houses when buying, most lose their
seal by 15-20 years—so, efficiency goes way down because the gap between the
panes is breached, they fog and collect moisture, et c. Replacing is so cheap
that even minor problems aren't considered for repair, as labor's similar
either way.

"I could charge you $400 to fix this, or $500 to replace it, and the newer
ones are slightly more energy efficient, and this one'll probably develop more
problems soonish. UV/IR coating on this is torn up anyway, those things rarely
last more than a few years, especially with young kids or pets, kind of a
joke. Give you a deal—say, $2250—if you just wanna do all 5 on this side of
the house so they don't look different, and to get ahead of problems on the
others". That kind of thing.

------
hourislate
There are two simple things a home builder/renovator can do to make any
dwelling super efficient. Insulate with Spray Foam and install a Geo Thermal
HVAC system.

The problem is when you tell the customer that Spray Foam at 3" / per sq/ft
costs approx $3 dollars (approx 16-20k to insulate a 3000 sq/ft home)they look
at you like you raped their sister and killed their mother. Yet when you quote
them a kitchen for 40k they smile and have no problems paying $140 a linear ft
for counter tops or $10 a sq/ft for carpeting. Cosmetic items can be replaced
at anytime (hardwood floors, tiles, kitchens, etc) but try to rip off all the
drywall in your home to re-insulate or dig/drill up your property to install
geo thermal.

People need to invest more into the mechanical structure of the home instead
of the cosmetic details if they are serious about building an efficient
dwelling. The building code at all levels needs to reflect a higher level of
efficiency and government programs in the form of tax credits should be used
to promote these upgrades and it would go a long way in helping reduce
emissions.

I keep telling people that Spray Foam and Geo Thermal is free. It pays for
itself rather quickly while providing a comfortable environment to live in.

~~~
sarcher
Spray foam products are excellent for a variety of reasons, but their effects
can be overstated concerning air sealing (one of the techniques in the
original article - I know you aren't directly addressing air sealing in your
comment). Spray foam provides excellent air sealing immediately after install
in as little as 1.5 inches[0].

However, spray foam also doesn't address wood-to-wood contact areas where air
leakage can occur. The best air-sealing results are typically achieved with a
taped exterior sheathing layer, or a taped sheet membrane (located on the
interior, exterior, or mid-wall). The most common air-sealing method that
works is the use of Huber Zip panels with Zip taped seams (or another quality
acrylic tape). One caveat - I say most common because it is a very common
material, but that doesn't mean the correct air-sealing methods are always
used.

[0][http://www.greenbuildingadvisor.com/articles/dept/musings/ai...](http://www.greenbuildingadvisor.com/articles/dept/musings/air-
leakage-through-spray-polyurethane-foam)

~~~
hourislate
When most houses are built the mechanical is typically an after thought. If
you look at commercial buildings they typically design the building around the
Mechanical. I have seen Schools, Grocery Stores, etc, spray-foamed from the
outside to prevent the hot/cold air from even entering the building. The
basically spray the inner substrate and of course you still have brick ties so
you can brick the outside of the building. You just need to leave some extra
room on the footings to allow for 3-4 inches of spray-foam.

A modern day house when built and finished has approx 2000 ft of linear cracks
in it. It is the equivalent of keeping your front door open all year around.
There have been test cases done where two homes are built exactly the same but
the insulation in one of them is spray-foam. They then do a blown door test
and the results speak for themselves. The spray-foamed house has almost no
leakage.

Here is a couple great sites for anyone in NA to learn more about spray-foam.
Demelic is based in Grand Prairie TX and in my opinion makes excellent foam.
BASF is another great foam also.

[https://www.cufca.ca/](https://www.cufca.ca/)

[http://www.demilec.com/](http://www.demilec.com/)

------
swsieber
So, all of this seems to apply to house _construction_. What's the best way to
retrofit a house, to make make it more energy efficient? Or is there no way
and I should just weep bitterly?

~~~
bovine3dom
Insulating your attic is the most effective and cheap thing for most people;
cavity wall insulation is more expensive but also effective if you have the
right kind of wall.

Then it's unexotic stuff like making sure doors have decent seals on them.
Double glazing is pricey and some way down the list.

Retrofitting better insulation to your walls if you don't have cavities is
very expensive (you'll have to redecorate the house, too) but effective.

~~~
sarcher
Most likely your house has double glazed windows - I only see single-glazed
windows in antique wooden windows these days (but perhaps it's different
outside of New England).

Good triple-glazed windows are expensive, but there are some vinyl triple
systems that are reasonably priced. Anderson and Pella both have triple glazed
options, for example.

There is also a relatively inexpensive (compared to imported European windows)
option for tilt-turn windows now available:
[http://logicwd.com/](http://logicwd.com/)

I haven't installed them myself, but I've bought other systems from that
vendor and have been happy.

~~~
swsieber
How can you tell if a window is single, double or triple glazed? Is there an
easy way, or would I have to have a specialist look at my windows?

~~~
sarcher
Generally, an easy way to figure it out is to look at where the glass
intersects the frame. On a single pane window you'll see the interior frame, a
gap (the glass) and the exterior frame. On a double pane you'll see a gasket
between the frames that separates the two panes. On a triple pane you'll see
two gaskets separating the three panes.

The gaskets maintain an airspace between the glass panes, which is responsible
for most of the thermal performance. On new windows this can even be filled
with a transparent gas (like argon or krypton) to increase performance.

------
nwah1
In developed nations, most people live in urban areas, and urbanization is
continuing. In many cities, building costs are smaller than the unimproved
value of the site. Around half the value is a typical figure.

Although, in certain districts in San Francisco, London, and New York the
average land-to-building ratio is near 90%.

Sort on the land share column on this data sheet, and you'll see that SF is
near that. Don't have data offhand for London, but given the reporting on it,
it actually seems higher.

[https://datatoolkits.lincolninst.edu/subcenters/land-
values/...](https://datatoolkits.lincolninst.edu/subcenters/land-values/metro-
area-land-prices.asp)

------
mmagin
The thing that annoys me is that both good passive solar design and utilizing
the lessons of "vernacular architecture" are both crippled by trying to make
houses that have roughly the same appearance that people are familiar with.

~~~
tveita
Do you have any examples of what unfettered designs might look like?

~~~
mmagin
Not really, I'm a dilettante at this.
[https://en.wikipedia.org/wiki/Village_Homes](https://en.wikipedia.org/wiki/Village_Homes)
is one of the more successful developments that really focused on passive
solar design that I'm aware of.

------
nvahalik
I've always been really curious to know how ventilation is supposed to work.

In an RV if you're cooking or venting in the shower the directions pretty
clearly say something to the effect of "open a window"—those things are sealed
pretty tight and the air you're pushing out needs to be replaced with
something...

So when you are taking a shower and use a ceiling vent (louvered, I assume)
where does the replacement air come from if you're sealing up the house?
Otherwise you'd just be creating a pressure difference and the fan wouldn't be
moving a lot of air. What am I missing?

~~~
jaclaz
The issue with a whole lot of "new" and "energy saving" houses is often
connected to poor ventilation.

Set aside for one moment the vapour from the shower, and from either the dryer
or coming from the natular drying of washed clothes, there is the human
generated vapour and that created by cooking.

In modern houses (without an efficient ventilation system) the airtightness
causes condensation/moisture (usually in corners of the rooms or wherever
there is a thermal bridge) which usually evolves in this (or that) form of
mould or mildew.

Some (not all) heat insulation materials make the walls (besides airtight)
also watertight, which makes the issue worse.

The idea of creating openings to allow the air in, which may be good in - say
- a kitchen where the air also exits normally via the extractor hood or
chimney (at the cost of some energy/heating/cooling dispersion) does not work
in other rooms, where the openings most of the time either do not guarantee
the circulation of air or behave as "heat dispersion" holes, negating all the
savings that the airtightedness gave you.

Not only, people breath and emits, beside vapour, C02.

I know that it sounds obvious, but if you don't let (fresh) air in, before or
later you will find yourself in a low-oxygen environment.

Having "normal", not airtight, windows and doors makes continuous ventilation
of the interior of the house a "natural" phenomenon (with a cost in energy).

If you make an "airtight" house, additionally "watertight" (as an example
using polystirene or similar for heat insulation) you are essentially living
in a unhealthy environment, unless you provide a suitable ventilation system,
and a ventilation system without an air-to-air exchange (to re-use part of the
heath or cold) will negate most of the saving effects of the added
insulation/airtightedness.

So, as pointed out by PoachedSausage, heat recovery ventilation is an actual
_need_ in energy saving houses, but it is still rather uncommon.

~~~
nsxwolf
It should be noted that pretty much any mold related repair is going to
potentially blow away years of energy savings, so you really need to make sure
your moisture control situation is in order.

~~~
noir_lord
My rented property has a master bedroom that is west facing & has a massive
tree in in front, that wall never gets the sun so consequently it gets surface
moisture, it's a pita every winter, this year I redecorated and am getting a
heavy grade dehumidifier to see if that helps, also shifted the heater during
decoration so it sits at the bottom of that wall.

------
nickhalfasleep
It's interesting to think about a few code changes to reduce the cost of a
house too. What if you removed the 120V outlets and wiring from bedrooms and
went to just 12V, or USB, or Power over Ethernet) for lighting and small
appliance power? A smart "Home Computer" that was the whole home. With more
efficient lighting, entertainment, you could cut down on the amount of copper
in the building, and the expectation of energy usage.

Of course keep the power places you need it, like the kitchen, bathroom, or
entertainment center.

~~~
brians
How do you vacuum? When you need to use power tools, just run cords or stick
to batteries?

~~~
agumonkey
I wonder if there are low power alternative to vacuum, depending on the
surface of course.

For actual power tools well.. I help my kids like indoor biking :heh:

~~~
ashark
> I wonder if there are low power alternative to vacuum, depending on the
> surface of course.

If the famous vacuum cleaner repairman Reddit AMA is to be believed, the
overwhelming majority of vacuums purchased are so in name only, producing far
too weak a vacuum to do any good and relying on carpet-damaging powerful
brushes to do the cleaning. So we don't even have working light-ish vacuums,
let alone low-power ones, let alone _affordable_ light and low power ones. The
ones that actually do what they're supposed to are still heavy and expensive
(and, I assume, power hungry).

~~~
noir_lord
I have one of the first generation Dysons that just won't die, it definitely
works as a vacuum cleaner, never use the rotary attachment.

GF has a German brand hoover I always forget that has insane suction.

~~~
njarboe
Have had a Miele vacuum for over 25 years. Still works great, rarely use the
rotary attachment. It was about $700 though.

~~~
noir_lord
Miele! that's the one, that thing is an engineering marvel.

Controllable suction, attachments that clip together with incredible
precision, the thing feels put together rather than slapped together.

------
chiefofgxbxl
One thing that I still have yet to see in the United States is a house that is
designed without central AC. An energy tip I see quite a bit is to program
your thermostat. But why can't I program my thermostat on a _per room_ basis?
[0]

If I'm on my computer at night and just want to heat my room, why do I instead
have to heat the entire house/apartment? What a waste!

I think this is still achievable using existing systems. Keep the central
unit, but modify the air ducts to have programmable valves. Then you can
choose which rooms to have the ducts open/closed to. Sure, there will see some
loss, but much better than maintaining temp for the entire building.

[0]
[https://s26.postimg.org/6ewi90rk9/rooms-e1442847765216-1024x...](https://s26.postimg.org/6ewi90rk9/rooms-e1442847765216-1024x709.jpg)

~~~
sliverstorm
Owning a better built house and having sealed it up and all, it turns out it
doesn't seem like that would help terribly much. With good design, heat gain
or loss is very limited in the first place. We get most of our heat from a few
south windows, and body heat. Once I shade the windows, it will be just
bodies, which heat the house the same no matter the room.

Plus the building is usually designed as a unit- the envelope is sealed and
insulated, room-to-room is not at all.

So the heat or cool just one room strategy I think is only compelling in a
poorly designed building.

------
wolfwyrd
This came from the Zero Energy Project[1] which also has floor plans.

[1] [http://zeroenergyproject.org/2017/07/24/simple-techniques-
lo...](http://zeroenergyproject.org/2017/07/24/simple-techniques-lowering-
cost-zero-energy-homes/)

------
WalterBright
My house has large eaves on it. This shades the house in summer, and keeps the
walls and windows dry during the Seattle rain. This really cuts down on
maintenance costs.

The house is also designed to use the "stack effect" to passively cool it in
summer, though experience with it shows it could have been done better.

I didn't care too much to super seal air leaks, because of potential indoor
air quality issues.

~~~
blacksmythe

      >> didn't care too much to super seal air leaks, because of potential indoor air quality issues.
    

It is more energy efficient to open your windows each day (during the optimum
daily temperature window), than to have low-level air flow all day.

The time of day that you want air flow varies with the season.

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neuromancer2701
This is all within the paradigm of convention construction.

The thermal properties of compressed earth brick(CEB) make heating and cool a
house a lot different. It would be interesting to see what the financial
number are if CEB were used instead of modern stick housing.

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ge96
That name seems misleading... "zero-energy" and then lower zero?

