|
|
comparing a super-house with super-windows vs. a sunspace house
6 nov 1996
dave robison writes:
>new super-windows are r3-r5, which is pretty good.
but super-prices and lower solar transmissions are not.
nor 5 year guarantees. what happens after the argon leaks out?
consider 2 houses on an average day in philadelphia in december, with an
average outdoor temperature of 36 f and an average 1,000 btu/ft^2/day of sun
that falls on a south wall: a super-house with 200 ft^2 of r5 super-windows
in the r20 south wall, with a solar transmission of 60%, and a house with a
32' wide x 16' tall x 12' deep lean-to r0.8 polyethylene film sunspace on the
r20 south wall, with a solar transmission of 92%, covered with shadecloth
in the summer, with just a few windows in the house wall proper, and a 16'
x 48' x 2' deep shallow frozen pond, made from a single 20 x 50' piece of
epdm rubber in front of the sunspace that augments the solar input by 30%:
super-house sunspace house
solar gain 120k btu/day 612k btu/day
thermal loss 43k btu/day 123k btu/day
cloudy day loss 43k btu/day 20k btu/day
net energy gain 89k btu/day 489k btu/day
(26 kwh/day) (143 kwh/day)
cogen possiblities:
solar closet no yes
water heating no yes
pv no yes
summer solar gain 120k btu/day 0 btu/day
house wall
maintenance more less
sunspace glazing $25 and 2 hours
recycling none every 5-10 years
gutter
maintenance more none
lawnmowing more less
water storage 0 gallons 12,000 gallons
skating rink no yes
tertiary sewage
treatment pond no yes
duckweeds, ducks,
frogs, goldfish,
bass, reeds, etc. no yes
mosquitos no ?
aesthetics "pretty" a matter of taste
resale value n/a ?
removable or
convertible to
a grape arbor, etc. n/a 1 day
privacy not good better
cost $8,000 $1,000
additional
wallspace for
bookcases, etc. 0 ft^2 512 ft^2
additional floorspace
for daytime use,
december gardening,
hot tubs, storage, etc. 0 ft^2 384 ft^2
second story deck no possible (8x32')
nick
|
|
