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re: insulation of shed ( nick, you out there? )
10 aug 2000
jim barr wrote:
>i have a new study in the garden!
congrats.
>a timber shed, 16ft * 8ft * 7ft high... there are 2 opening windows
>13" * 17" and 5 closed windows 21" * 17", all single glazed.
yoicks. about 15 ft^2 of us r1 windows and 128 ft^2 of ceiling and
321 ft^2 of walls... does this comply with the 2003 uk standards?
>the shed is not airtight but the leaks are not a major draught problem!
say 0.5 ach, ie 0.5x8x16x7/55 = 8 btu/h-f of draught conductance.
>...i would like to line it to reduce winter heating bills, cost is a factor.
so, investing in insulation at some interest rate saves ongoing fuel. say
it's heated to 20 c with electricity costing 10 cents/kwh for 40 hours per
week for 3 months when it's 0 c outdoors, but wait, you posted this in the
renewable energy newsgroup!
>the studding is 45mm thick [1.77 inches?] so i can either have 19mm
>polystyrene [3/4" beadboard] (double) or slightly compressed 50mm [2"]
>rock wool. or ????
the rockwool's probably cheaper, with almost as much insulation value,
but yucky as an interior finish. the beadboard might be left exposed,
or painted off white (latex) for a curious indoor tudor look.
how about rockwool, then a single layer of beadboard, then vertical 1x3s
screwed over that to attach the beadboard to the studs? that gives us r3
for the beadboard plus about r6 for the wool, about us r9 (ft^2-f-h/btu).
add 6" of rockwool over the ceiling, and the total conductance is about
15ft^2/r1 = 15 btu/h-f for the windows plus 321/9 = 36 for the walls plus
128/20 = 6 for the ceiling plus 8 for draughts, 65 btu/h-f altogether.
your 100 watt (341 btu/h) body can warm the shed 341/65 = 5 f over the
outdoors. making it 70 f on a 0 c day requires (70-32)65 = 2470 btu/h, you
and 2129 btu/h of other creatures, eg a 687 lb ashrae-standard calf, or 5
ashrae-standard 79.3 lb goats, or 6 ashrae-standard 50.0 lb dogs, or 31
ashrae-standard 6.61 lb cats, or 36 5.41 lb ashrae-standard rabbits, or 140
ashrae-standard 0.9 lb guinea pigs, or 1290 ashrae-standard 0.046 lb mice.
hope this helps,
nick
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