SASKATOON'S SUPERINSULATED HOUSE

Article Tools

Image Gallery

Print

E-mail

Comments

RSS

Each of the builders then received a $6,000 compensation for the additional expenses that often go hand in hand with energy-efficient construction. (It's estimated that some $5,000—or about 6%—of the cost of each project home resulted from the superinsulation features. However, builders are finding, now that they've constructed a number of these houses, that this expense can be reduced.) The residences ranged in price from $65,000 to $120,000 in Canadian dollars, with the average being around $85,000 ($1.00 Canadian equals roughly 80¢ U.S.). The approximate cost per square foot was between $40 and $45... again, in north-of-the-border currency. All of the homes were built on speculation and are now owned privately… and the buyers of the energy-efficient dwellings received a discount on their mortgage interest rates for taking part in the program.

SUPERINSULATION
Many folks—when they first hear the term—likely think that "superinsulation" involves nothing more than cramming every nook and cranny with fiberglass batts. But while the Energy Showcase houses do have more insulation than the norm, their efficiency is equally dependent on several interrelated construction details, which include the following:

• A continuous air/vapor barrier. The home's shell, basement, and ceiling are literally shrouded with sheets of 6-mil polyethylene . . . which are carefully overlapped and joined with acoustical sealant, a pliable butyl rubber compound.

• An air-to-air heat exchanger. These uncomplicated blower-augmented machines continuously suck fresh air into the house while exhausting stale air ... thereby removing odors and pollutants, reducing humidity, and reclaiming heat at the same time.

• Careful attention to glazing. The Energy Showcase homes typically have a window area equaling 5 to 10% of the total heated floor surface, a proportion similar to that of other houses in Saskatoon. However, all the designers tried to locate the majority of the windows toward the south to take advantage of solar gain, and they employed triple and/or quadruple glazing.

THE DOUBLE WALL
The Canadian builders found that the most convenient way to incorporate all the features necessary to minimize air leakage and retain heat inside a dwelling (and a superinsulated house is, above all else, an airtight structure) is to use double-wall construction (see the accompanying diagram).

Essentially, the technique involves building two stud-framed walls (the interior one is load-bearing), with the air/vapor barrier placed behind the inner wall. Insulation is sandwiched between the studs of both walls. (This kind of construction allows most of the electrical, plumbing, and ducting work to be located within the interior wall, thus maintaining the integrity of the vapor barrier.) The R-values of the double walls used in the Energy Showcase homes varied from R-30 to R-60.

RSS | Comments | E-mail | Print