
Thermos-Like Passive Homes Aggressively Save Energy - ph0rque
http://news.nationalgeographic.com/news/energy/2015/01/150120-thermos-like-passive-homes-heat-up-in-the-us/
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Someone1234
Even "nice" homes in the US seem built out of the cheapest building materials.
Just a minimal framing, a couple of girders, and then everything else is
medium-density fibreboard prefab junk. It is like living in a very sturdy
tent.

They try to make up for how poorly the walls are constructed by shoving tons
of insulation (mostly hazardous-during-deconstruction fiberglass) but really
it is just nothingness. I'm sure with a wood axe I could literally chop my way
into someone's bedroom from outside.

In much of Europe both new and old homes are built using brick(!). These homes
have already lasted over one hundred years and will likely last at least
another fifty or more with normal maintenance (e.g. roof repair, replacing
some plumbing, etc).

Most US homes seem to have a lifetime of around 50 years before they get
demolished and replaced by identically terrible homes. Except there are a few
places in the Eastern US where older homes were built well (e.g. Maine) but
newer ones are built like junk.

I'm not surprised they're bringing in building materials from Ireland. I doubt
anyone in the US produces real homes anymore.

~~~
dragonwriter
> In much of Europe both new and old homes are built using brick(!). These
> homes have already lasted over one hundred years and will likely last at
> least another fifty or more with normal maintenance (e.g. roof repair,
> replacing some plumbing, etc).

AIUI, Brick construction is actually less resistant than wood-frame to many
kinds of things including -- particularly relevant to California residents --
earthquakes.

Its less resistant to axes, sure, but then that just means that modifications
are less expensive -- but its not exactly like hostile attacks by axe against
homes are that common.

~~~
gchpaco
Unreinforced brick construction is actually illegal in many parts of
California, possibly all. It's pretty easy to reinforce, though; if you sink
rebar through the brickwork every now & again, it's as resilient as concrete
and arguably prettier.

Admittedly this is much easier in new construction...

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elihu
> So far, it has been defined by the German standard that limits the heating
> and cooling load to 4,755 British thermal units per square foot (or 15
> kilowatt hours per square meter)—about one-tenth that of homes built to
> current U.S. codes.

In the comments section, there's a clarification that this is per year. (Kind
of a shame to see "unit fail" in a publication that should know better.)

I'm kind of curious to know what sort of new technology (if any) makes high-
efficiency targets easier to meet these days. The article talks about triple
pane windows and thick walls. Are these stick-frame houses with fiberglass and
offset 2x6s in the walls or something like that, or are there new materials? I
recently read that aerogel has been coming down in cost to the point where
it's plausible that someone with deep pockets might insulate their house with
it if they didn't want super thick walls. Insulated concrete forms and
autoclaved aerated concrete are also something that some builders use. What
else is new?

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danpat
It's partly materials, but there are lots of factors:

\- building codes raising the bar, which has brought down costs for what used
to be "fancy" materials

\- improvements in building science

\- increased energy costs driving demand for improved efficiency

\- greater awareness of energy consumption amongst the population

I've renovated a few houses build in the 60's and 70's in Canada. As far as I
can tell, they had the materials and knowledge to make far more efficient
houses, but much of the time, it was just easier, quicker and cheaper to
install a big-ol' heater and drive the cold out. With a few simple and
relatively cheap building envelope modifications and a more efficient heat
source, it wasn't difficult to bring heating costs down by 50% or more.

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sandworm
There are dangers in sealing home so tightly to control energy use. Blocking
the escape of hot/cold air saves on the bills but can lead to condensation
problems when the mechanical systems fail or are not designed perfectly.

Even something as simple as replacing an electric range with a gas one
(burning gas is a huge source of moisture) can lead to mold in the long term.
A clogged vent into a basement can see moisture from a gas water heater creep
into wood on the inside the impenetrable vapor barrier.

And don't get anyone started on the dangers of off-gassing from new
construction materials in an airtight environment.

~~~
patcheudor
There are a number of mitigating technologies which can be used to maintain
quality indoor air. Our home has a heat exchanger to bring in air from the
outside & venting in the mechanical room which is on a timer to exhaust any
buildup of products of combustion from the gas furnace and water heater. The
crawl space is also vented to avoid a build-up of radon gas. Interestingly,
the homes used as an example in the article are getting mini-splits which
don't have venting capabilities. They are awesome and I love the one we have
in our home theater, but am afraid that when they are the only solution used
for heating and cooling in a well sealed home the important issue of venting
the home properly and in an energy efficient manner may not be addressed. With
a central air system it's relatively easy and cheap to do an external heat
exchanger. With a mini-split solution, a dedicated heat exchanger system would
need to be installed separately from the main source of heating and cooling.

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walkamages
There is a horrible trend of sealing homes up tight, and then we start to
notice a raft of problems developing - in the fabric of the home, and it's
inhabitants. I am lucky to live in a 1930's building in London, with plenty of
ventilation built it. It is certainly not the most eco rated property, but, it
is healthy. It might cost a couple of pounds more to heat over the year, but,
it has proven itself over time, from coal fires, to back boilers, to central
heating, air flows throughout, damp does not get a chance to thrive, nor mould
nor fungi nor other related issues.

~~~
danpat
Houses with poor ventilation will have problems, but sealing buildings up is
good for energy efficiency. "HRV" (heat recovery ventilators) are common and
required by code in many cold climates (Canada, northern Europe) which do
whole-house ventilation with a heat exchanger so you're not just blowing all
your nice warm air straight outside when it's -40C all week.

The German Passivhaus standard shows what can be done with this approach, and
it works very well.

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madengr
Many of these new energy efficient homes are built for low-income/no-income
housing. The middle class who have to pay for their homes themselves can't
afford the construction methods, solar panels, etc. Easy to do if you are
using someone else's money. Funny thing is these HUD houses won't last long at
all because the copper and other precious materials will be torn out and sold
for drugs.

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danielharan
"The windows are one of the most expensive features,"

The obvious follow-up is what the 80/20 might be on these features. If going
with readily available double-pane windows shaves $10,000 off the cost, it may
be a decent trade-off - maybe use that money to buy some solar panels instead,
aiming for net-zero?

~~~
dsr_
Even the best available windows are not very good. My not-very-special house
has R-17 walls; expensive triple panes windows can go to U-0.15. U values are
1/R values, so that's a whopping R-6.

If your roof is in good condition, points the right direction and is
unobstructed by trees, solar power is probably a better economic bet than
replacing decent windows with super-windows.

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mcmancini
Don't these also have poor indoor air quality since they don't frequently
exchange air with the outside?

~~~
o_____________o
Yes, with the upshot being that a purposeful entry point for air allows for
targeted temperature control and cleaning in the duct.

A sizable living wall/vertical garden would be pretty cool in a home like
this.

