Superinsulation means super savings in Canada's cold
When you look at Don and Glynis Granger's annual heating bill, you might think they lived among the flamingos on the Florida Keys. The Grangers, in fact, live in moose country, near Lake Ontario, where temperatures plunge below zero with impressive regularity during the winter.
Yet the Grangers paid a mere $37.90 to the electric utility company and burned about a pickup-truck load of wood - ''principally for aesthetic reasons, '' they say - to heat their 1,800-square-foot home for the entire 1981-82 heating season.
The reason they can accurately state the costs is that they had a separate meter installed expressly to monitor the power used by the electric furnace.
A letter from Ontario Hydro confirms the low cost. The bill for the 1982-83 season ran about $30, because of the milder winter.
To this cost add about $3 a month to run the air-to-air heat exchanger during those months when no windows are opened to let in fresh air. Even so, ''the need to budget for heat no longer exists,'' says Don Granger, who teaches urban planning at Mohawk College in nearby Hamilton.
Mr. Granger worked on the layout for a development composed entirely of superinsulated houses here on the outskirts of Guelph and became so fired up by the idea that he bought the first home.
He could ''understand the logic of superinsulation'' and expected the new home to work well, ''but not quite this well,'' he says with emphasis. Mrs. Granger, by contrast, was highly suspicious of claims being made for superinsulation and is ''totally delighted'' with the results, she says.
Granger calculates the low-energy package may have added as much as 10 percent to the overall cost of the home, compared with conventional construction. But, he says, ''the reduced energy bills will pay for that extra cost in five years.''
Canadian superinsulated houses, or low-energy houses, as they are sometimes called, were developed on the prairies of Saskatchewan, where temperatures of 40 degrees below zero (the point where Celsius and Fahrenheit scales cross) are commonplace.
Heavy insulation, and what may be termed ''total tightness,'' is the key to the success of the low-energy houses.
John McColl and David Braden, who built the Granger home, speak for all low-energy home builders: ''Insulation isn't worth a hill of beans if there are holes in the vapor barrier.''
During construction they fix a hole ''instantly,'' much as a patch is applied to the inner tube of a flat bicycle tire, and take three days, rather than one, to put in windows so they can make sure they don't leak air. There's no other way to go, Mr. McColl and Mr. Braden contend.
The company title, Airtight Building Company Ltd., of Guelph, Ontario, reflects the importance they place on a no-leak house.
The message of superinsulation is slowly getting across to the public in much of North America, Braden says. During the Easter holiday weekend, some 500 people came out to this rural community to look over these low-energy homes and 200 the following weekend.
''People are beginning to believe that the super-efficient house is a possibility and they want to see one for themselves,'' Braden says.
The low-energy house was developed in Saskatoon, Saskatchewan, about four years ago and ''set the world on fire,'' according to Braden.
Keith Hanson, an engineer with Victory Homes in Saskatoon, was one of the pioneers. Mr. Hanson was involved in the design and erection of one of 14 original homes, which ''have been tested and monitored beyond compare'' by Canada's National Research Council, Hanson told the recent ''New Neighborhood'' conference in Toronto.
Two constraints were placed on the designs of any house that could qualify for the term ''low energy.''
The house had to cost less than $100 a year to heat in Saskatoon's climate, and all materials used had to be applicable to conventional construction. Hanson's company designed and built a 1,200-square-foot bungalow with attached garage and solarium that met these constraints.
Providing the additional insulation and ''total tightness'' added $6,000, or some 7.25 percent, to the cost of the home, compared with a single-wall home with 6 inches of insulation. However, it is still cheaper to own the more expensive home.
When heating bills for the region are included with mortgage costs, monthly payments for the more expensive house run to some $8 under those for the cheaper home.
Bankers, now well aware of the impact of heating costs on bank foreclosures, even accept a lower qualifying income for the more expensive superinsulated house.
The Granger home is typical of many of the Saskatoon low-energy homes - double walls of 2-by-4 framing timbers (31/2 inches when planed) that are set 5 inches apart. This allows for a total of 12 inches of insulation when the two walls, plus the intervening cavity, are filled.
The polyethylene vapor barrier is placed on the cool side of the inner-wall framing timbers. This allows all electrical wiring and plumbing to be placed inside the interior wall without having to cut any part of the vapor barrier.
The National Research Council of Canada, in its ''Design and Construction of Low Energy Houses in Saskatchewan'' (Building Practice Note No. 30), describes the construction this way:
* The wall is built in the horizontal position on the house floor. The interior structural frame is constructed first, straightened, and squared in preparation for sheathing.
* The polyethylene (6-mil) is placed on the cold side of the inner frame and lapped over the top and bottom plates and end studs.
* The sheathing (5-sixteenths-of-an-inch plywood or particle board) is applied, care being taken to protect the air-vapor barrier when the sheathing is cut to size and to ensure its integrity at window and door openings.
* The exterior frame is then constructed on top of the sheathed interior wall. Window and door openings are constructed to match exactly the openings in the inner frame.
* When the exterior frame is complete and squared, it is raised onto temporary supports so that the space between the inner and outer frames can be set. Plates of plywood (5 sixteenths of an inch) are nailed to the top and bottom plates to hold the frames at the proper spacing. This completes the framing of the wall.
* When the wall is raised to the vertical position and properly located on the floor, it is nailed into place. It now remains only to brace the wall at the ends. No further straightening is required before putting on roof trusses or floor joists for the next stage of construction.
The continuity of the vapor barrier is provided by a bead of acoustical sealant applied wherever two sheets of polyethylene join.
For a copy of ''Design and Construction of Low Energy Houses in Saskatchewan (Building practice note 30),'' send $1 to cover postage and handling to Division of Building Research, National Research Council, Montreal Road, Building M20, Ottawa, K1A 0R6, Canada.