re: please help me design an insulated bed tent for my cold attic room
7 dec 2004
>i live in san francisco, where it rarely gets colder than 50f. however,
>i live in a refinished attic room that has no insulation on the walls
>and ceiling. its basically shaped like a a frame with the celing about
>15' high in the middle and the floor is 15'w x 25'l and carpeted.
an equilateral cross-section...
>i want to be able to sleep and hang out in a warm area... maybe 65 or 70f
>and about 8'w x 15'l. my thought is that i should be able to design and
>build (relatively cheaply) an isulated bed tent that looks decent and
>can hold the warmth put out by an electric space heater.
you might build a smaller version of the room itself, eg an a frame made
from 8 $11 4x8 pieces of 1" double-foil "r7.2" polyisocyanurate board, with
an 8'x8' base and an 8' ridge. use foil tape to join the pieces or attach
them to a 2x3 frame. with 2 people inside and no thermal mass, the inside
temp would quickly rise about 600btu/hxr7.2/256ft^2 = 17 f. you might add
collar beams and tuck this tiny room up under the ridge. thomas jefferson's
house had insulated bed compartments. so did old swedish farmhouses.
or build a larger room under the collar beams, with the roof as one wall
parallel to an 8' vertical wall in the middle of the space and a 4' wide
ceiling and an 8' wide floor. if this were 16' long, it would have 13x4x8
= 416 ft^2 of exterior surface. with 2 people, dt = 600btu/hxr7.2/416ft^2
= 10.4 f, or 600/[176ft^2/r7.2+240ft^2/r20)] = 16.5 f, if you add 3.5" of
r13 fiberglass insulation over the 4'x16' ceiling, under the new loft area,
and between the foamboard and the sloping wall, and behind an endwall.
a 100 w light bulb would add another 9.4 f.
you might build it airtight, and add herbach and rademan's (800) 848-8001
http://www.herbach.com $4 21 cfm 7.4 watt tm97fan2963 fan to blow air in
near the ceiling through a one way plastic film damper on the inside and out
through a hole near the floor, in series with h&r's nice brass $4.95 navy
surplus humidistat, item number tm89hvc5203, wired to close over 60% rh,
and put 2 light bulbs in series with their $2.50 tm92hvc2293 thermostat
mounted near the ceiling.