Fixing window drafts is easier than it sounds. As the weather cools, wind may be bent on finding a way into your house,
but you’re equally determined to stop them and stay toasty warm.
Here’s how you can keep cold drafts from getting in via a poorly insulated
window. Spring-metal or V-shaped vinyl weather-stripping works
very well and is almost invisible.
Review the installation diagrams to determine the exact location and orientation for the product you're using. Clean all surfaces well, especially if you'll be using adhesive-backed weather-stripping.
Partially open both sashes so you can access the front edge of the horizontal meeting rail on the upper sash. Install the weather-stripping on that rail with the point of the V facing up (see B) or the nailing flange at the top. Cut and install additional strips equal to the sash's width to seal any gap between the top of the upper sash and the head jamb as well as between the bottom of the lower sash and the sill. Secure the strips to the top of the upper sash and to the bottom of the lower sash.
Clean the surface well. Cut adhesive-backed tape to fit the perimeter of the area you will cover, and then press it into place.
Use a hair dryer on a low setting to warm the film. This shrinks it and pulls out any wrinkles. Carefully trim the excess with a single-edge razor blade or sharp utility knife.