How to Stop Drafts in Old Windows

Drafts are the silent thief of home comfort and energy efficiency. In older homes, the sash often shifts away from the frame over time, creating thin channels where air sneaks in to chill your rooms. Addressing these leaks is one of the most effective ways to stabilize your indoor temperature without expensive replacements. Done well, your windows will operate smoothly while keeping the breeze outside where it belongs. You are not just blocking air; you are reclaiming the insulation value of your wall assemblies. This process is straightforward, requires minimal tools, and provides immediate relief during the cold months.

1. Clean Every Surface First. Scrub the entire frame and sash edges with soapy water to remove years of dust, grime, and peeling paint. Dry the surfaces thoroughly to ensure the adhesive on your weatherstripping bonds correctly.
2. Cut to Exact Length. Measure the vertical tracks and the top and bottom rails where the window meets the frame. Cut your V-seal or foam weatherstripping to these exact lengths to avoid overlap at the corners.
3. Press Down Hard. Peel the backing off the weatherstripping and press it firmly into the track or frame where the sash meets the wood. Ensure you are applying it to the surface that makes direct contact when the window is closed.
4. Bridge Every Tiny Gap. Inspect for small remaining holes at the corners where the stripping meets. Apply a small bead of paintable silicone caulk to bridge these tiny gaps and lock out the air entirely.
5. Shrink Film Smooth. Clean the window casing with rubbing alcohol to remove grease. Apply the double-sided tape provided in the kit around the perimeter of the casing, press the plastic film into place, and shrink it tight with a hair dryer.
6. Find Hidden Leaks. Light a stick of incense or use a damp hand to trace around the window edges on a windy day. If you feel movement or see the smoke drift, identify the spot and add extra seal or tape.