Draft-Proofing Your Home for Winter: Where Cold Air Gets In and How to Seal It
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If your furnace runs constantly and one room still feels cold, you probably don't have a heating problem — you have a gaps problem. Cold air sneaks in around doors and windows all winter, and warm air leaks out the same way. The good news: most of those gaps can be sealed in a single weekend with basic materials and no special skills.
Step 1: Find the drafts first
Don't guess — test. On a windy day, hold a thin strip of tissue paper near the edges of your exterior doors and window frames. Where the tissue flutters or gets pulled, air is moving. Run your hand slowly around the frame too; a steady cool stream on your skin is a leak. Mark each spot with painter's tape so you can work through them one by one.
Step 2: Seal door and window frames with weatherstripping
For gaps around the frame itself, self-adhesive weatherstripping is the standard fix:
- Wipe the frame clean and let it dry — adhesive won't hold on dust or moisture.
- Measure each side of the frame and cut the strip to length with scissors.
- Peel the backing and press the strip firmly along the frame where the door or window closes against it.
- Close the door or window and check the fit. It should close snugly without you having to force it. If you have to slam it, the strip is sitting too proud — reposition it slightly.
Our Self-Adhesive Weatherstripping — Door & Window Seal Strip (D-Profile) comes on a 10-metre roll, enough for several doors or windows around the house.
Step 3: Block the gap under the door
The gap at the bottom of an exterior door is often the biggest single leak in the house. An under-door draft stopper slides or sticks along the bottom edge of the door and sweeps the gap shut every time the door closes. Measure your door width, cut the stopper to fit, and check that the door still swings freely. Our Under-Door Draft Stopper is a cut-to-fit foam roll made for exactly this job.
Step 4: Tape window gaps and seams
Older windows often leak at the sash seams and corners, not just the frame. A clear draft-proof sealing tape pressed over those seams stops the leak while still letting light through and letting the window look like a window. Apply it on a dry day, press out air bubbles as you go, and run a finger along the edges to seat it. See our Window Insulation Sealing Tape for the clear tape we stock for this.
Step 5: Re-test
Go back with the tissue strip and check your marked spots again. The flutter should be gone or much weaker. Whatever spots remain are your list for next weekend.
Draft-proofing won't fix a worn-out furnace or missing wall insulation — but for the common frame-and-gap leaks, an afternoon of sealing is the cheapest comfort upgrade in the house. Start with the door you use most, and work your way around.