Windows are a leading cause of heat loss in many homes. Adequate weatherstripping helps prevent air leaks, and keeping your windows in good condition is also a wise preventive measure. But it's just as important to make sure the area around windows is well sealed and insulated.
If you know how to use a caulking gun and if you have a putty knife or screwdriver, you are ready to properly insulate your windows. The video below provides a good demonstration of the techniques you should use.
Exterior Wall Windows - Apply sealants around all windows. Sealants can eliminate drafts, provide thermal resistance, and keep out moisture, dust and insects. The sealants you will be using are generally of two types: caulk and urethane foam.
Caulk is a paste-like material that cures to a solid state. It is applied with a caulking gun to seal small cracks or gaps. As you apply the caulk to these small spaces, move at a slow, steady pace, forcing caulk into the gap. Smooth excess caulk with your fingertip or a putty knife before it dries.
Urethane foams are liquid materials that expand rapidly as they set to a semi-rigid state. They are used to fill larger gaps and holes. The most common type is available in an aerosol can or large canister. To apply urethane foam, follow the directions on the label. Place the nozzle over one end of the gap, and then squeeze the trigger while dragging the nozzle across the gap. Because this material will expand, do not overfill the gap.
Use small scraps of insulation to fill in the cracks around windows and doors. Separate the insulation from the facing and use a putty knife or screwdriver to work it into spaces between studs or anywhere you can see daylight. This is an important quality step on every job.
Basement Windows - If there are windows in your basement wall, you can make a metal window frame and attach it to the walls around the window. Cut out insulation and tuck it behind the frame to finish. Another method is to attach furring strips to the wall around the windows and staple insulation to the strips, then tape.