This Green House: Windows and Doors

They’re big, leaky holes. Plug them in to save money.

This Green House
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It’s cold in my home office and the window is to blame.

It’s one of those big sliding patio doors. Despite loads of weather stripping, I can still feel a chill breeze coming through it and even see frost forming in some of the corners. I really should replace it, but with what?

Windows, doors and skylights can account for up to 25 per cent of a home’s energy loss, reports Natural Resources Canada — a shocking amount, when you consider how little space they take up in your home.

Basically big holes

“I would describe windows as the weakest part of the wall assembly,” said Jamie Van Gelderen, president of Performance Haus Inc., which sells energy-efficient building products in the Edmonton region.

This was a combination of materials and design, he explained.

Glass simply isn’t a good insulator—as a demonstration, grab a glass of hot water and see how quickly you feel the heat.

A window is basically a hole in your wall insulated with glass, said Leigh Bond, president of Boundless Renewables Consulting in St Albert. Whereas a standard Alberta wall has R20 in terms of insulation, most efficient windows top out at about R8, meaning they lose heat more than twice as fast as a wall. (R-values ​​measure resistance to heat loss. An R1 wall loses one unit of heat per hour per square foot per degree Fahrenheit of temperature difference. An R10 wall loses one tenth of a unit.) While you can get R18 windows from the Edmonton -based company LiteZone, those still aren’t as efficient as a basic wall.

Most windows average less than R2 in terms of insulation, said Mike Lieske, a St Albert resident and longtime renovations sales specialist with All-Weather Windows. Modern fiberglass doors average R13, while older steel ones run at about R8, with wooden ones as low as R4.

Design can also make a window less efficient. Sliding windows use felt strips instead of rubber gaskets, which make for a leaky, incomplete seal when they close, Van Gelderen said. A crank-shut or casement window has rubber gaskets, but the unsupported weight of the cranked-out window can cause it to sag and leak. Tilt-and-turn models (which tilt or turn open inward instead of outward) don’t have the sagging problem, and are the best for long-term performance.

Tech considerations

You know it’s time to replace your door if it’s cold, drafty, or has frost around the frame or lock, Lieske said. An efficient door should have at least R13 insulation, fiberglass construction, rubber seals all around, and an adjustable striker plate. Check the Energy Star website for examples.

Van Gelderen said an efficient door costs $2,000 to $2,500, which is pretty close to the price of a regular door.

An inefficient window will be drafty and may have leaks or ice build-up, Lieske said.

Van Gelderen and Lieske said an efficient window should have triple-pane glass, argon gas, and two Low-E coatings for roughly R8 insulation. Again, check the Energy Star site for examples. You can get quadruple-pane windows, but those are typically too thick and heavy for most walls.

“Triple-pane is kind of the ideal at this point,” Lieske said, as it gives you about half an inch of insulative air-space to disrupt heat transfer. Replacing that air with argon adds even more insulation.

Low-E coatings are layers of silver oxide which bounce heat back into a home, Lieske said. Cold places like St. Albert should stick with two coats of Low-E 180 for warmth. Hot areas such as BC should seek a Low-E 270 coat, which stops heat from getting into your home to keep it cooler.

Expect to spend about $1,000 to $1,200 on an efficient window, or about $200 more than a regular one, Van Gelderen said. Lieske said an efficient window or door will pay for itself in energy savings after 10 to 15 years, although you can often recover their costs through the boost they give to a home’s resale value.

Door and window upgrades are expensive, but they’re also eligible for CEIP funding. The Canada Greener Homes program offers $125 to $250 grants per window or door to a maximum of $5,000. Van Gelderen said window and door replacements should be done in parallel with wall insulation, air sealing, or new siding, to cut down on costs.

According to an online calculator run by Cardinal Glass Industries (a major glass manufacturer), an existing 2,000-square-foot, two-storey, east-west facing home in Edmonton that replaces its regular windows with triple-paned, argon-filled, double Low-E 180 coated ones would save about $427 in energy annually and prevent some 5.2 tonnes of CO2 emissions a year.

Whatever windows or doors you get, Van Gelderen and Lieske said it is vital for you to have them installed by a professional.

“A window is only as good as its installation,” Van Gelderen said, and a bad installation can lead to more leaks and damage.

Lieske said he put efficient windows into his St. Albert home, and found they made it cheaper to run and more comfortable to live in.

“We love it. It’s minus 30 out and you can slap your hand on the glass and it’s not cold.”

Green Actions
Action: Replace double-paned windows with triple-pane, argon-filled, Low-E 180 coated ones
Cost: $1,000 to $1,200 per window
Payback: 10-to-15 years
Savings: $427 and 5.2 tonnes of CO2/year
Greener Homes rebates: $125 to $250 per window/door, up to $5,000
CEIP eligible: Yes

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