Jan 11, 2024

11 Tips for Window Air Conditioner Maintenance

BTUs, or British thermal units, is a measurement that reflects how much energy an air conditioner uses to remove heat in an hour. A window unit with about 6,000 BTUs, for example, can cool up to a 250-square-foot room like a bedroom. See the sidebar below about portable air conditioners.​

Before installing the unit, clean the windowsill and immediate area. Remove any obstructions, such as curtains or blinds, so cool air flows freely.​

A window unit, especially a larger one, may need a mounting bracket to support it and keep it level, home inspector Miles says. The manufacturer's instructions will note if a bracket is required and will provide it. Put the bracket up first because it will help steady the unit during installation, he adds.​

Check your local laws and building codes. Some ordinances require using support brackets for safety reasons.​

Follow the manufacturer's instructions for installation. Some DIYers may be able to install a smaller window unit themselves, but many units are heavy (40 to 100 pounds) and require a helping hand to install. Ask a family member, friend or neighbor to assist you. In addition, nonprofit groups in many areas offer handyman programs for older adults; check with your local senior center to see what is available in your area.​

Once installed, lower the window so it sits tightly against the top of the air conditioner. Extend the unit's side panels to block the gap between the unit and the window frame, using screws to secure the panels if needed. Use foam insulation or weather-stripping tape to seal any remaining gaps to prevent air leaks. Consider installing window locks for safety.​

Paul Bees, 65, an executive recruiter who lives in St. Paul, Minnesota, uses insulation and foam around two window units so cooled air doesn't leak out. For the larger unit, which sits over a basement egress window, he had to build a wooden "contraption" to support the unit. ​

Don't forget to plug it in. You’re ready to go.​ ​

Consider a freestanding air conditioner on wheels (also called a windowless air conditioner) for a small space, if you want to move the appliance between rooms or a window unit is banned by your landlord or homeowners association.​

They’re inexpensive and easy to install, but they have limited cooling capacity and use more energy than window units or central air conditioning. These units draw in warm air, use refrigerant to cool it and release it into the room; the warm air is vented outside.​

The two main types are single-hose units, which are less expensive but less efficient, and dual-hose units, which cool faster and more efficiently with separate intake and exhaust hoses. Most units come with a window installation kit, including a vent hose.​

Portable air conditioners typically cost about $100 to about $650, depending on the type and size. That compares with about $200 to $850 for a window unit and several thousand dollars for central air conditioning. ​

Rust isn't an issue because portable units stay indoors, but mold can form inside. Experts recommend similar inspection, cleaning and maintenance steps as for window units — all DIY possible. Before purchasing, home inspector Miles suggests checking if the portable unit contains a washable air filter or a HEPA filter you must buy and replace.​​​

Sheryl Jean is a contributing writer who covers aging, business, technology, travel, health and human-interest stories. A former reporter for several daily metropolitan newspapers, her work also has appeared in the Chicago Tribune and The Dallas Morning News and on the American Heart Association's website.

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