re: building with icfs in new england?
23 dec 2002
>my wife and i expect to be building a home next year. it will be a two-story
>with basement, in central massachusetts. whatever our heat source is, it'll
>be ducted forced-hot air around the house (not solar or wood fire).
solar can work with ducts or baseboard radiators...
>if we go "conventional" on the framing, we'll use exterior 2x6" stud walls.
sips are comparable in price, and better insulators, and fast to assemble.
>i've just heard about insulated concrete forms (icfs), and we're intrigued.
>...the benefits seem enormous: quiet, efficient (effective r- values up to
>r-50 are claimed)...
that means very little, unless you live in a climate where
the average outdoor temp is very close to the indoor temp.
>...making the house so extremely tight seems to encourage... people to bring
>fresh air in in a managed way. what are people doing for that? i've seen
>references to air-to-air heat exchangers; what brands/models are worth
these are now required in all new houses in minnesota. you might look for
an approved list. a manufacturer on the list is likely solvent enough to
bribe politicians, and its products might be less likely to catch fire :-)
>...is there a better/simpler way to do it?
make the house as airtight as you can (the standard for a new swedish house
is 0.025 ach, 40x tighter than a typical us house), then
a) turn on a ventilation fan with a humidistat if it gets too humid
in wintertime, or
b) let warm indoor air move up the inside a chimney while moving cold
outdoor air down between another pipe surrounding the inner pipe, or
c) divide the house into 2 partitions and turn on a small periodically-
reversing fan between them as needed to turn all the house envelope
cracks and crevices into very efficient bidirectional heat exchangers.