When the chill of winter sneaks into your living room even with the heat cranked up, a drafty window is often the culprit. Those invisible streams of cold air not only make your home feel less cozy but also drive up your energy bills. The good news is that you don’t need to be a professional contractor to fix the problem. With a few simple materials and a little bit of time, you can seal up those leaks and make your home much more comfortable. Let’s walk through the process of finding and fixing drafty windows.

First, you need to know where the air is coming from. On a windy day, hold a lit incense stick or a candle near the edges of your window. If the flame flickers or the smoke drifts sideways, you’ve found a leak. Common spots include the gap between the sash and the frame, the joint where the window meets the sill, and any cracks in the putty around the glass. Sometimes the leak is not even at the window itself but along the trim where the window frame meets the wall. Check those areas too, because a small gap in the molding can let in just as much cold air as an open sash.

Once you’ve located the problem, you can choose the right tool for the job. For the moving parts of the window, weatherstripping is your best friend. This flexible material comes in several forms, like adhesive-backed foam tape, V-strip, or felt. Foam tape is the easiest to apply. Just cut it to length, peel off the backing, and press it into the gap along the top and bottom of the upper and lower sashes. V-strip, which looks like a thin plastic runner, is more durable and works well for sealing the side channels. Felt is cheap but less effective, so it is best for windows that are rarely opened. If you have a sliding window, the same approach works once you understand which edges contact the frame.

For the stationary cracks, such as where the window frame meets the wall, you will want to use caulk. A simple tube of silicone or acrylic latex caulk and a caulking gun is all you need. Cut the tip of the tube at a 45-degree angle, load it into the gun, and carefully apply a smooth bead into the crack. Then run a wet finger or a smoothing tool over the caulk to press it in and create a nice seal. Let it dry completely before painting, and you have a permanent barrier against drafts. Another quick fix is rope caulk, which comes in a roll and can be pressed into gaps by hand. It’s not as durable as tube caulk, but it removes easily and works great as a temporary solution for a single winter.

Another great option, especially for older windows that are beyond simple weatherstripping, is clear plastic film. This temporary solution involves taping a large sheet of shrink film over the entire window and then using a hairdryer to tighten it. The film creates an insulating air pocket that blocks drafts while still letting in natural light. It is not the prettiest solution, but it is affordable and works wonders for a single season. When spring arrives, you can peel it off without leaving much residue. Just be careful with the tape – use the kind designed for this purpose to avoid damaging your paint.

Of course, not every draft comes from the edges. Sometimes the glass itself is the weak point, especially if you have single-pane windows. In that case, adding a layer of insulating window treatment, like heavy curtains or cellular blinds, can help. Or you might consider a temporary storm window panel, which snaps into place on the interior and provides an extra layer of protection. These are great if you rent and cannot make permanent changes. You can also buy a roll of insulating film that is slightly larger than your window, cut it to size, and attach it with double-sided tape – it’s a five-minute project that makes a noticeable difference.

Before you start, take a few simple precautions. Clean the areas where you will apply weatherstripping or caulk, because dirt and old residue will prevent a proper seal. Also, work on a warm day if possible, as cold weather makes materials harder to handle. And always measure your windows carefully, so you buy the right amount of material. A little extra is fine, but running out mid-project is a hassle. If you are using a caulking gun for the first time, practice on a piece of cardboard to get the hang of the trigger and the speed of the bead. It sounds silly, but it saves you from messy mistakes on your actual window.

By taking the time to seal your drafty windows, you will notice an immediate difference in how your home feels. No more chilly spots near the glass, no more whistling sounds on windy nights, and no more paying to heat the outdoors. Your heating system will run more efficiently, which is good for your wallet and the environment. Plus, you have the satisfaction of knowing you handled it yourself, one more small victory for your home improvement skills. So grab a candle, find those leaks, and get ready to enjoy a warmer, cozier home this season.