Sealing leaks to save energy

Home Truths

Little known fact: Your house breathes. A typical home is supposed to exhale about 33 per cent of its air every hour, sparing your lungs from mold, dust and other tiny invaders.

My house doesn’t breathe. It hyperventilates. Every hour it purges about 75 per cent of its air – which is fine for my family’s health, but it kills me to think that we pay to heat that air and then quickly set it free.

Job No 1 – locating the leaks – was a challenge. My home has foam insulation, fiberglass insulation, insulated windows, weatherstripping and enough caulk to seal a ship. How exactly does 75 per cent of my air escape every hour? I posed the question to residential energy specialists, and in the process learned some tricks – a few of which will also help apartment dwellers, who usually have no worries about foundation cracks or attic insulation.

Finding a leak is easy, they said. Get a blower door, which depressurises a house so that even the tiniest drafts blow like a stiff wind. Second choice: a laser thermal leak detector, which will identify the cold spots that coincide with leaks.

Incense to reveal leak

The most cost-effective sleuthing device, though, is even cheaper and may already be in your home – a stick of incense. Pick a breezy day and pass the burning stick near any seam in your house, and the smoke will reveal where the leak is. I took a lighted incense stick around my doors and windows, and the technique worked fairly well, even if I grew completely sick of the smell after a while.

But it was later found that I’d missed some spots I hadn’t even thought to check, like the seam between my fireplace and the wall, and my baseboard heaters. My two biggest omissions were the attic and the basement. “If your attic access is inside the house, that’s a big one to watch for,” an expert said. “If it’s not well sealed, it’s like leaving a big door open.”

At some point in the last few years, I lost a bolt that secured one of the two big springs in my drop-down attic ladder, leaving one corner sagging about a half-inch from the ceiling. I never considered the effect that sag might have on my budget until I envisioned air streaming through the gap.

As for the basement, “Check the places where all your piping is coming and going,” another expert said. “Sometimes things happen, like your house might settle, and it’ll open a pretty good-sized crack.” To spot those leaks, try this: Go to the basement in the daytime, but keep the lights turned off. Depending on the angle of the sun, you may detect cracks from the daylight shining through the foundation.

This exercise actually solved two mysteries. The pipes to my outside water spigots apparently travel through holes big enough to accommodate much airflow – and many mice. Basement doors are another area of vulnerability, since people often pay little attention to how well they’re constructed or maintained. In my case, the frame was surrounded with gaps that had probably been there the entire decade we’ve lived in the house.

Last, a word to those with central air or central heat: Try the incense trick around the seams of the ductwork. Even a small gap can allow costly leaks. Now on to Job No 2 – plugging the leaks. You’ll need to spend some cash – except in one area, that is.

Every place I’ve ever lived has had a front door draft, and just about every front door nowadays has a threshold with three big screws. But those screws don’t simply keep the threshold in place. Turn them counterclockwise and the threshold rises, closing out the source of a nagging draft. When the weather turns warm and humid, you can reverse the process if the door is too tight to close. Thus ends the cost-free portion of this process.

If your doorway lacks adjustable thresholds, install a rubber door sweep. Weatherstripping, widely called foam, is also a must, for doors and windows. If you have an unheated section of basement, be sure the door to that section is firmly sealed – unlike mine, which has a hole for a cat door cut into it.