re: building an energy efficient home
12 apr 2003
iain blackie wrote:
>the recipe is simple, though there are many variations.
>lots of south facing windows - free solar gain
in the uk? :-) i woulda said "minimal windows," with a low-thermal-mass
isolated sunspace to provide lots of house heat on an average winter day.
>more draught proofing and insulation - reduces the losses
i've read the swedish standard for new houses is 0.025 ach, which requires
a fan with a humidistat or a concentric chimney or a reversing partition fan
for "shurcliff lung" ventilation. some us sip builders guarantee 0.2 ach.
we might do better homemade, with staggered 4'x8' sheets and glue and deck
screws, like this, viewed in a fixed font:
_ ooooooooooooooooooo r0.5 $ 5 osb
fffffffffffffffffff 7.2 11 atlas 1" double foil polyiso board
ff fff ff 3.2 2 1"x3" foamboard spacers
5.5" fffffffffffffffffff 7.2 11 atlas 1" double foil polyiso board
2x4 2x4 2x4 3.2 6 vertical 2x4s
_ fffffffffffffffffff 7.2 11 atlas 1" double foil polyiso board
ooooooooooooooooooo 0.5 5 osb
| 4' | r29.0 $51, about $1.60/ft^2 for materials.
this weighs about 3 lb/ft^2. three people might tilt up an 8'x24' wall.
>concrete floor with insulation going vertically down around the
we also need insulation under the slab where i live.
>the massive heat store for dec and jan
more windows make it massiver. i favour a 4'x8'x8' tall box.
>recover heat from your greywater
maybe 300' of 1" plastic pipe in a drum.
>hot water solar panels
no. shelves in the upper part of the box, behind their own glazing, and
a 42 gallon pressurized galvanized tank in the lower half of the box.
>above all - do it cost effectively. money is a great motivator.
yes. with about $1/ft^2 of solar energy per year, any single-purpose
"solar collector" that costs more than $10/ft^2 has a difficult time
paying for itself.