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re: manufactured homes
30 mar 2000
grey wolf responded thusly:
>>...in a very cold climate, leaving the underside of the house
>>open to the winter breezes makes floors very cold.
>not if it's
>1. insulated
>2. has a permeable barrier to minimized the effects of the breeze.
how many angels, how many pins?
on a 30 f day, a 70 f house with r20 insulation under a 12x50'
floor with 12'x50'/r20 = 30 btu/h-f of thermal conductance and
a) a "minimal breeze" whistling under the floor loses about
(70f-30f)30btu/h-f = 1200 btu/h or 864k btu/month through
the floor, something like 8 gallons of oil. in scenario
b) with no underfloor breezes, and r10 skirting, 2' tall,
(eg 2" of styrofoam), with a few closed foundation vents and
a vapor barrier on the ground and about 2(12'+50')2'/r10 = 25
btu/h-f of skirt thermal conductance, with about 1/(1/25+1/30)
= 13.6 btu/h-f of floor to outdoor conductance, the floor loses
about (70-30)13.6 = 545 btu/h or 393k btu/mo, something like
4 gallons of oil.
plastic bags full of r50 strawbales would lose less heat.
nick
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