A metal window seal can let drafts into your home if it's not insulated properly. After you insulate the seal, you will no longer be wasting energy in your home, because your metal windows will be more efficient, which can help to save you money on home energy bills. If you use the right material to insulate your metal window seal, you won't have to worry about reapplying the insulation until the next season.
Get the right caulk to insulate your metal window seal. Use a silicone construction grade caulk. If construction grade is not available, use household grade.
Remove any old caulk from around your metal window seal. Use a putty knife to carefully scrape it away. Then clean up the area with a cloth and white spirit.
Let the entire area dry completely before you start to apply the silicone caulk.
Load the caulk into your caulking gun.
Point the gun at the edge of the window frame between the glass and the frame. This is the area to seal to insulate the window. Apply a thin, even strip of caulk all the way around the metal window frame.
Release the trigger of the caulking gun. Then gently pull it away from the metal window. This will leave a smooth finish.