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The two key energy efficient ideas we used were super-insulation
and solar energy. To understand the principles behind these click
here.
Super-Insulation
The idea is to keep the heat in (or out!),
and it's not much more complicated than putting on a coat in the winter.
There are various ways to do this: double 2x4 walls, a 2x4 wall sheathed in
3" of foam board, SIPs, or strawbale walls. Combined with this use R3
(U=.34) double glaze windows, or even better yet use R5 (U=.2) triple glaze
units everywhere you don't what solar gain. The latter are only available
from a couple fo manufactures in Canada.
The house should be built a
fairly "tight", meaning that it doesn't leak a lot of air.
To do this, use spray foam (or equivalent) around all the framing cracks and
penetrations before insulating, and then, as an added barrier, consider filling the walls
with a dense insulation, such as cellulose or foam, although this step isn't as
important. All insulations have some tradeoffs: click
here for more detailed info). A housewrap, which could be just tar
paper, and rainscreen siding will also act as an air barrier. There has
been some controversy about building "tight" houses, mostly having to
do with mold problems and "sick building syndrome". It's
important to know that even a tight house leaks will in the range of 30 to 70 cubic feet of
air a minute (about 2000 cubic feet an hour), while a typical house probably
leaks 2-5 times that amount. When the wind blows or its cold out, or a door or window
is opened, or an exhaust fan is used, the air leakage goes up from
that. Tights house don't lack in fresh air. The important point is
to make sure you eliminate excess indoor moisture, use low toxic building
materials and keep toxins out of the house (for background: click
here. For example details click here.) One
nice benefit to thick walls, is deep window sills (see photo).
Solar Energy
Start by finding a
location that gets a lot of sunshine, which
in cities pretty much means its on the north side of an E/W street and not on a
north facing slope. The biggest issue in cities in having your sunlight
blocked by other buildings or trees. Sun in the west is so hot in the
summer, that if its not block, then shading is usually desirable.
Put the majority of windows on the south side, and then
arrange
them to have an overhang, so that on June 21st, most of the glass is shaded by
the overhang (not the same warmer climates). The easiest way to free solar
energy is to have about 7% glass on the south side (to find out what that means,
click here.) This won't maximize how
much solar energy you use, but it allows you to use solar energy with no
additional cost. In cloudy Seattle, doing this reduces your heating
requirement by about 25%.
Additional energy can be achieved using solar hot water collectors, on the roof
or elsewhere. For an example of this click here...
Other issues It is fairly easy to get quite energy efficient appliances,
and although the best ones tend to cost more, good ones can be had at reasonable
prices. In 2004 we found a top rated refrigerator at Sears, and ones
that are pretty close at many appliances places (for ratings see www.energystar.gov).
The most efficient refrigerators also tend to be lower cost, since they have
fewer features. In dishwasher and washing machines, the more efficient models
tend to be the more expensive, but in this case, they also have additional
features. We're sold on PEX plumbing, using the "home
run" configuration.
While you should still try to locate plumbing fixtures near the hot water
heater, the skinny PEX pipes deliver hot water fast, saving both water and
energy (heat lost from the pipe after you turn the water off). Click
here for a construction example. Daylighting
in homes isn't that hard: put windows on two walls in most rooms, and avoid having
oversized windows. In north facing room, skylights can be used to great advantage.
Divide electrical lighting into ambient lighting (not super bright) and task lighting (bright, but
only in a small area), rather than make the entire room bright enough to read
in. Compact fluorescent bulbs are much improved in both color and
longevity, and new innovative bulbs are expected to hit the market by 2010. Computers
are huge electric hogs, although laptops are much better, especially if they
hibernate when not in use. Put plug strips on TVs and other devices with
remotes, to keep them from using power when they're not on (they use power
sitting there waiting for you to press "on" on the remote control!).
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