Saturday, September 29, 2012

"Net-zero" housing

Unfortunately, the build cost is estimated at $600-800k. I'm more interested in the (presumably cheaper) insulation technologies than in the solar panels. See here for energy usage by housing type; a significant chunk of total US energy consumption goes to heating and cooling buildings.
Atlantic Monthly: ... NIST believes that this home – with 10 kilowatts of photovoltaic panels on the roof, and another four solar thermal panels over the front porch – will generate as much energy as a four-person family can consume in a year. This is, in other words, a “net-zero” house.


Richard Seiter said...

I agree with you about the relative merits of insulation (and other efficiency) technologies versus solar PV. It is interesting that they (apparently) chose not to have solar hot water heating or passive solar design features. I wonder how they heat their water. I did not see much detail on the technologies used (e.g. is the heat pump on the right ground sourced?). What frustrates me about demonstration projects like this is how many people really need a 2700 ft^2 home (along with a 1500 ft^2 unfinished basement)? If someone really wants that (and is willing to pay for it), fine, but I think promoting that as a model is counterproductive.

I would recommend that anyone interested in renewable energy and efficiency technologies for home use check out Home Power magazine:

David Coughlin said...

We've cut $100/month off of our winter heating bills as we have renovated our 85 year old house, mostly by insulating.

esmith said...

Seems like a serious waste of taxpayer money. Why is this needed? There
are tons of net-zero houses here in California. According to the most
recent state statistics, there are around 80,000 residential properties
in the state with photovoltaic installations. 10 kW is overkill (at
least here), an average house here can have net zero electricity usage
with 4 kW. That's about half of all installations, 40,000 net zero

It does not cost $600k either. At the current rates, a
DIY photovoltaic installation can go as low as $2/kW (if you have usable
space on the ground and you don't need to hang panels on the roof),
it's not particularly hard to do.

Still, insulation is much
cheaper, that's the first thing to do. You need to have at least R30
(ideally R60) in the attic, energy-efficient windows, sealed drafts
around doors. Then you can start thinking about PV.

Richard Elder said...

Or you could build a net near zero house that actually pays attention to the earth and sun and costs less to build than the tract house replica shown---.

but the neighbors and zoning natzis might object.

Richard Seiter said...

That site looks interesting, but I did not see any complete projects described. Do they have any example houses with cost breakdowns and technological details? (or do you have any other recommendations for that kind of information?)

coldequation said...

Did they take into account the energy involved in building and maintaining that monstrosity, amortized over the likely lifetime of the house?

Robert Sykes said...

The cost of the electricity generated by solar (and wind) installations is around ten times the cost of that produced coal-fired power plants. Also, such installations only produce power about 10% of the time, so it is really a fossil fuel-powered system with occasional solar (or wind) supplementation. To ice the cake, solar and wind power systems do not reduce carbon dioxide emissions, and once they exceed a few percent of installed generating capacity, they destabilize the power gric.

Installations like this exist only because there are very large government subsidies paid to the manufacturer. The subsidies come from our taxes.

David Coughlin said...

My sensibility on this is that if you are going to go solar, you need to go all the way and get batteries, too.

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