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3 Things You Need to Know About Air Conditioning

AC Know-How
AC Know-How

Ah, the sweet relief of a cool, dry house after a hot, sweaty afternoon of yard work. Like any mechanical system, AC needs a little TLC to run smoothly, including many tasks you can tackle on your own. We asked This Old House plumbing and heating expert Richard Trethewey to share his know-how for central air and window units.

SEE ALL: Everything You Need to Know About Air Conditioning




1. You've got to change the filter
Dirty filters kill your AC's efficiency, so install a new one every month during the cooling season for central and window units (or clean them if you've got the washable type). Look for the filter's minimum efficiency reporting value, or MERV, which ranges from 1 to 12 for home AC units; the higher the number, the better filtration it provides (and the more energy needed to pull air through it, so balance air-quality concerns with energy costs).

2. It would serve you well to fix air leaks
Ducts can lose up to 30 percent of airflow through leaks, and window AC units are notoriously tough to seal properly. Find leaks using the old "smoke trick": For window units, light a stick of incense and hold it where the unit and the window frame meet; for central AC, hold the stick near duct connections. If the smoke blows around, you've got leakage. For ductwork, use foil tape to seal small gaps and duct mastic for larger ones; for window AC units, stuff foam between the device and the window frame, taping as needed.

3. There are benefits to using a timer
There's no need to blast the AC at full tilt while you're at work. For central units, install a programmable thermostat that lets you set higher temps when you're gone and cooler temps when you're home. Newer window units have built-in timers and adjustable thermostats, or you can buy a timer at any home store for $10 to $20; just make sure it matches your device's voltage. Unless you're going on vacation, don't shut off the system; otherwise, the air compressor will need to work harder to cool your house later.

See 6 more musts for keeping your AC in shape to keep you cool and save some money!

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