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How to Insulate My AC

Marshal M. Rosenthal

A portable air conditioner (AC) provides a convenient way to cool a room without having to do an invasive installation on a wall. The downside is that the air exhaust hose that transfers heated air from the AC also lets outside air back into the room. To eliminate outside air from being able to enter, insulate the exhaust hose that exits the house. The procedures are straightforward and require supplies from a hardware store. Household tools are also needed. No electrical skills are required.

  1. Remove the exhaust hose from the portable AC unit. Stretch the hose fully out. Wrap a thermal tape around the entire length of the hose, starting at one end and ending at the other end, to insulate it. Wrap the plastic from a plastic food wrap around the entire length of the hose. Smooth the wrap onto the hose with your fingers. Tape the wrap to the hose at the front and back using strips of duct tape. Return the hose to the AC unit.

  2. Remove the end of the hose from the portable AC unit. Slip a dryer exhaust hose over the AC hose. Push the dryer exhaust hose down the length of the AC hose. Reattach the AC hose to the AC unit. Place the end of the dryer exhaust hose against the AC unit where the AC hose is seated. Wrap strips of duct tape around the end of the dryer exhaust hose to secure it to the AC unit.

  3. Measure the diameter of the portable AC unit's exhaust hose. Purchase a flexible duct that has this diameter. Cut a hole through the wall, using a drywall handsaw, that is the same dimensions as the duct. Place the duct in the wall. Apply insulation foam from a spray can to the sides of the duct on the outside and inside of the house. Place the exhaust hose into the flexible duct. Tape the end of the hose to the sides of the duct using strips of foil duct tape.