Should I Run My Air Conditioning All Summer Long?

Lots of homeowners worry about running their air conditioner too long. They want to save energy, or they don’t want to cool rooms that don’t need it. So they only turn on the A/C when it’s really warm out.

That seems like common sense, but there are actually different schools of thought on this issue. In fact, some people worry about running the A/C too little. Why’s that?

For one, when your house is very warm, it takes a lot of energy for your air conditioner to cool it down. The surfaces of your home all store heat—from your roof, to your walls, to your windows. And the greater the temperature differential between indoors and outdoors, the longer the air conditioner has to run to reach the target temperature. So it’s reasonable to think that if you leave the A/C running at a consistent temperature, your system won’t have to work as hard to keep you cool.

That may be true in the short term, but it can create unexpected consequences in the long term.

One big issue is “short cycling.” If your home is always close to your target temperature, your A/C only needs to run for a few minutes to cool it to the proper level. That shorter cycle may be long enough to reach your target temperature, but it’s often not long enough to dehumidify the air. Too much humidity can make your home feel warmer than it actually is, so you may end up running to the thermostat to turn it down even lower.

Also, short cycling isn’t the most efficient way to run your air conditioner. Think of the impact on your gas milage when you drive your car in stop-and-go traffic versus cruising along on the highway. For maximum efficiency, you want your A/C to cruise, not crawl. It can also be noisy. Many homeowners find it irritating it is to hear their system constantly turning on and off.

So, should you run your A/C at the same temperature, all summer long?

We recommend the “cruise control” option. Run your A/C when you need it, and let your programmable thermostat handle it when you don’t. Ultimately, you will save energy—and money—by running your system fewer hours per year.

Image credit: Jeremy Levine/Flickr. CC license.