3. Warm air is leaking in. Check the seals around your window AC to make sure hot air isn’t getting in and cold air isn’t seeping out. Reseal around your unit with weather stripping if necessary.
“Most new window units come with insulation panels to place over the plastic adjustable side panels,” says Chris Regan, who oversees our air conditioner tests. “But to maximize efficiency, you’ll still need to use weather stripping around the perimeter of the unit. And always use the manufacturer’s installation and safety hardware.”
4. Your window AC is vibrating. Air conditioners make plenty of noise, including the whir of the fan and the sound of the compressor cycling on and off. But if you hear a vibrating noise, it may mean that your unit was installed incorrectly. Make sure it’s sitting securely in the window, and review the installation instructions in your owner’s manual to confirm that no steps were missed.
In this video, John Galeotafiore, associate director of home improvement product testing at CR, explains how to maintain a window AC unit to ensure cool, clean air.
