Beat the heat and tune up your air conditioner now

Last summer every state east of the Mississippi River recorded one of its 10 warmest summers on record so you probably don't need a reminder that it's good to have a capable air conditioner. To make sure you're ready for the next heat wave, give your unit a tune-up now so it'll work when you need it most.

Window air conditioners
Before you begin, check your owner's manual for any model-specific information on setting up the unit for the season. Typically, manufacturers recommend these steps.

Clean the filter. Remove the filter, vacuum it and then wash it in warm, soapy water. Let it dry completely before you reinstall it. If it's damaged, order a replacement model or buy filter material and cut a new custom size.
Vacuum the coils. Remove the unit from the window or wall sleeve and vacuum the indoor and outdoor coils with an upholstery-brush attachment. Use a soft brush or a can of compressed air to remove dirt and gunk from the inside of the coils and the base of the air conditioner.
Straighten the fins. As you handle and clean the unit, take care not to crush the cooling fins, which will make the unit less efficient. A specially designed fin comb (which you can buy online or at an heating-and-cooling supply store for $8 to $20) will straighten bent fins better and faster than a screwdriver.
Plug any leaks. Install weatherstripping around the unit if needed so cold air won't escape and hot air won't come in.

Central air conditioners
Homeowners with central air should have a licensed professional change all filters, clean and flush the coils, drain the pan and drainage system, and vacuum the blower compartments. The contractor should also check that the system is properly charged with refrigerant, free of leaks and that all mechanical components are working properly.

Homeowners should clear debris and dirt from the grills, condenser coils and filters every month and replace the filters when needed. Trim any vegetation within two feet of the unit. And check the pipe that drains condensed water from the indoor unit to make sure it is working properly and isn't leaking.

New air conditioner ratings
If your air conditioners can't be saved, check our new ratings of small, midsized and large window units.

—Gian Trotta