Sealing on the outside of your home not only prevents air from entering, it can also prevent damage to siding, walls, insulation, windows, and doors due to moisture intrusion.
Hole for pipes, wires, etc.
Caulk or foam around openings for electric, gas, oil, and water-supply lines; drainage pipes; plumbing for outside spigots; cable TV and telephone cables; mail slots/doors.
Caulk or foam around dryer vents, heating and cooling system vents, and fresh-air supply vents for fuel-burning furnaces and water heaters.
Caulk around window frames. If you have combination storm windows, caulk around the windows where the metal storm window frame meets the window’s frame; don’t seal the moisture weep holes at the bottom of the frame. If you have wooden storm windows that must be exchanged for screens in the spring, use nonpermanent, non-staining rope caulk to seal the joint between the storm window and the frame.
Caulk around door frames. Install storm doors if needed and check latches and seals.
Seal the outside
There are many places to apply caulking or foam to weather seal the exterior of your home: