Caulking Windows and Doors - Outside or Inside?
Which is better? Caulking inside or outside windows and doors? The answer: Both!
Caulking along the outside of the frame of a window or door is important in sealing from water infiltration. Although some air could seep into the gap slightly, it makes little difference in air infiltration, but absolutely necessary in preventing water damage.
The caulking between the frame and the wall is imperative to keeping out cold, drafty air. Hopefully you have enough room between the wall and the window frame to use can foam sealant (window and door variety), But if not, caulking will seal just fine.
Type of Caulk
This may be the easiest item to find at the home improvement store ever. It says "Window/Door Caulk" on the tube. Pick a color and away you go.
This is a great project for some simple energy savings. You can caulk every window and exterior door on an average home (1500 square feet) in about 4 hours. Remember, attached garage doors count as exterior doors.