You asked:
>This is an inquiry if anyone has information about solar home designs,
>>especially envelope home designs. A few years ago an article was
>published in >Popular Mechanics (or Popular Science) about the method of
>building a home with >a double wall on the north, and a greenhouse on the
>south, with space in the >basement and attic for the air to flow around
>the house (and out the roof in >the summer), heating it in the winter, and
>cooling in the summer. The >particular home was in Lake Tahoe and the
>owners only used a wood burning stove >as backup to the heat from the
>greenhouse. (snip)
Based on my recollections of envelope houses built in Oregon in the late
70's and early 80's, I would urge caution. There was a lot of interest and
enthusiam, but they had some problems.
Code officials had fire safety concerns about the double-walled plenum
space in the structure--fire dampers had to be installed, and the plenum
spaces had to be lined with drywall. Also, code required the large areas of
overhead glazing in the sunspace to be laminated-type glass, so that if
they broke and fell, the pieces of glass would be less likely to injure
occupants. These measures were not on the stock plans available at that
time and added extra costs.
The overhead glazing leaked and the glazing seals failed within the first
couple of years on one house.
The sunspaces were prone to overheat on sunny days because the
glass-to-mass ratio was very high and the passive air loop couldn't remove
heat fast enough. One owner found that passive solar heat alone would not
drive the air loop through all weather conditions, and added a fan to the
loop.
Also, resale raised the issue of appraised value for the buyer--appraisers
didn't know how to determine the value of a type of house and energy system
that they did not have comparable sales for.
I think you could build a solar home that was more livable, durable,
energy-efficient and had better resale value.
Mike
O'Brien & Associates
Environmental Building Consultants
Portland General Electric Earth Smart program
obrien@hevanet.com
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