How To Seal Window Air Conditioner — !!exclusive!!

Use a damp cloth with mild soap to clean the window sill, the sash, and the AC unit casing.

Your AC won't have to work overtime to fight incoming heat.

Adhesive-backed foam is best for filling narrow gaps along the window sash and AC unit base. how to seal window air conditioner

For an airtight finish, use specialized tape. Do not use standard duct tape, as it leaves a sticky residue and degrades in the sun.

When you open a double-hung window to install an AC, a large gap is created between the top of the lower sash and the glass of the upper sash. This is where most cooling loss happens. Use a damp cloth with mild soap to

Best for: Large gaps or those prioritizing maximum insulation.

When sealing a window AC, the materials you choose matter as much as the method. For an airtight finish, use specialized tape

💡 If you leave your AC in the window year-round, use an exterior fabric cover and an interior plastic seal during the off-season to block winter drafts.

Following these steps will make your room noticeably cooler (or warmer in winter if you leave the AC in), reduce your electric bill by 10–15%, and stop bugs and rain from entering.