Cold draft from a window or door

Q: Cold draft from a window or door

In Canada, when you feel a cold draft from a window or door, the most common cause is worn or compressed weatherstripping — a few dollars of seal you can replace yourself. On an exterior door, a missing or worn door sweep is the next thing to check, then gaps where the frame meets the trim, which take a bead of caulk. A window that won't pull tight often just needs its latch or hardware adjusted. Old single-pane windows leak no matter what, and there the real fix is an upgrade — a bigger job. Almost all of the quick wins are safe DIY; start with the cheapest seal and work up.

A cold draft is annoying on a Canadian winter night, but it's usually a cheap, weekend-sized fix — a worn seal or a missing sweep, not a window you have to tear out.

tuneWhat are you noticing?

Select anything that matches and the checklist below reorders to fit. Not sure? Skip it.

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Start here

In Canadian homes, check the weatherstripping first. Run your hand around the closed door or window edge and look at the seal: if it's flattened, cracked, brittle, or peeling away, it's no longer sealing. Replacing a strip of self-adhesive weatherstrip is a few dollars and the single most common fix for a draft.

Ranked from real-world failure data. The order updates as you select what you’re noticing above.

Likely causes, in the order to check them

Showing the typical order

Beginner-friendly Doable, with care Safety-critical Call a pro

handymanHow to fix it

Peel off the old weatherstrip, clean the surface, and press on a new self-adhesive foam or V-strip (or replace the door's kerf-in weatherstrip), sized so the door or sash closes snug without binding.

Peel or pull out the old weatherstrip and wipe the channel clean and dry so new adhesive will stick.
Measure each edge and cut new weatherstrip to length. Foam or V-strip is easiest for windows; an exterior door usually takes a kerf-in or nail-on strip that matches the frame.
Press the new strip in place along each edge, keeping it continuous at the corners so there's no gap.
Close the door or sash and check the fit: it should seal all around without being so tight it won't latch. Trim or re-seat as needed.

schedule30 min savings$8–30

Weatherstripping (foam / V-strip / kerf-in)Match the gap width and the type — self-adhesive foam or V-strip for windows, kerf-in or nail-on for exterior doors

gavel Check your province first AB: homeowner may do this · BC: homeowner may do this · ON: homeowner may do this · PE: homeowner may do this · QC: homeowner may do this
Replacing weatherstripping, door sweeps, exterior caulk, and window hardware is homeowner-permitted across Canada. Note separately: full window or exterior-door replacement (changing the unit or altering the opening) may require a building permit and, for egress or structural changes, a contractor — verify the municipal/provincial rule before that scope of work.

visibilityHow to check

Close and latch the window, then try to wiggle the sash by hand. Movement, or a visible gap at the latch side, means it isn't clamping down onto its seal.
Slip a slip of paper or a dollar bill into the closed seam and pull: if it slides out easily along one edge, the sash isn't sealing there.
Check the latch, keepers, and hinges for loose or worn screws. On a casement, the crank and its keepers pull the sash in; on a hung window, the latch and tilt latches do — see which one isn't drawing tight.

buildscrewdriver schedule10 min

handymanHow to fix it

Tighten or adjust the latch, keepers, and hinges so the sash pulls firmly against its weatherstrip when closed; replace a worn latch or keeper with a matching part if adjustment alone won't close the gap.

Tighten any loose screws on the latch, keepers, and hinges first — do it gently, since sash frames strip easily and over-torquing can crack vinyl or wood.
If the sash still doesn't clamp, reposition the keeper (the catch the latch pulls against) a hair toward the seal so latching draws the sash in tighter.
On a casement, adjust or replace worn keepers so the crank pulls the sash flush; on a hung window, adjust the latch so it fully engages.
Close, latch, and re-test with the paper slip. When paper drags along all edges and no air moves, the sash is sealing.

schedule30 min savings$0–25

Window latch / keeper (sash hardware)Match the window type (casement, single/double-hung, slider) and the existing hardware brand or hole spacing

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Why the list is in this order

We don’t sort by likelihood alone. We sort the way a good, honest tradesperson thinks: rule out the free, safe, common causes first. That’s why the cheap checks outrank the expensive repairs — and why anything dangerous gets a hard stop instead of a pep talk. The order exists to save you money, not to sell you anything.