How to Seal an Air Conditioner Vent for the Winter

Cold air can come through the air conditioner vent and any cracks around the unit during winter, which makes your home less energy efficient. By sealing it, you not only reduce the cost of heating your home, you protect your unit from harsh weather. If you have a lightweight window unit, consider removing it from the window and storing it for the season, as this makes it easier to seal any drafts.

Insulating AC cover
Plastic sheeting
Tape
Measuring tape
Rope caulk

Instructions

- 1
  Place an insulating cover on the outer portion of the air conditioner.
- 2
  Unplug the unit. Remove the decorative grill on the interior side of the air conditioner, and tape a plastic sheet across the front of the exposed unit to block air drafts. Leave a portion at the bottom of the plastic unsealed to prevent condensation, which can cause mildew. Reattach the grill.
- 3
  Clean the crevices along the outer edge of the unit to remove dirt and dust.
- 4
  Measure the length of each crack or crevice surrounding the unit, and tear off pieces of rope caulk at matching lengths.
- 5
  Dip each piece of rope caulk in water, and then press the pieces into the cracks with your fingers. Allow the caulk to dry. Remove the pieces in the summer when you unseal the unit.
- 6
  Seal the entire window or opening with a sheet of plastic if you feel any cold air when running your hand around the trim.

Robinair 25150 Instructions

How to Clean Cotton Off an Evaporator Unit

Air Conditioners