Here are better ways to use your air conditioner for energy and cost

For many people, beating the heat this summer means one thing: cranking up the air conditioner.

Experts say having access to air conditioning isn’t just about comfort. During extreme heat events, which are becoming more frequent and prolonged due to climate change, being in an air-conditioned space helps keep people safe.

But air conditioners can be expensive energy guzzlers. According to the Energy Department, air conditioning ranks as one of the biggest energy users in homes across much of the country – consuming about 6% of the nation’s electricity, at an annual cost of about $29 billion to homeowners.

There are, however, changes you can make to your space and how you use your air conditioner that can save energy, said Jennifer Amann, senior fellow in the buildings program at the American Council for an Energy-Efficient Economy, a nonprofit group. Even adjusting your thermostat a couple of degrees warmer than what you normally keep it at could yield savings that add up over time, Amann said.

“A few percent here and there can really make a difference over the course of the summer,” she said.

Understand your AC

In the United States, experts say people with air conditioning are likely using one of the following: conventional central air conditioning, window units, or various types of heat pumps, which include central systems that require ducts or ductless technology such as mini-split heat pumps.

Together with taking steps to keep your home cool, switching to a high-efficiency air conditioner could reduce your energy use by 20 to 50%, according to the Energy Department.

Industry groups such as the Air-Conditioning, Heating, and Refrigeration Institute and the Association of Home Appliance Manufacturers provide efficiency ratings and can be helpful resources for consumers, said Wes Davis, technical services director of the Air Conditioning Contractors of America, a trade group.

Proper installation and maintenance of air conditioners can boost efficiency. Routinely replacing and cleaning filters, for instance, can lower an air-conditioning unit’s energy consumption by 5 to 15%, the Energy Department says.

But Amann and other experts say how you run your air conditioner could also make a difference. Here are some energy-saving tips you can try:

Power down

Not running your air conditioner when you don’t need it can help cut down on energy use, but the savings often depend on a variety of factors, including how well your home is insulated, what type of system you’re running and the weather outside, said Aisling Pigott, a graduate student studying building systems at the University of Colorado at Boulder who has researched whether shutting off cooling actually saves energy.

In a published analysis that was not peer-reviewed, Pigott and other researchers found that less energy was used across the three types of air conditioners studied when cooling was shut off for an eight-hour period, compared to running the systems all day at 76 degrees Fahrenheit.

While the researchers noted that energy use temporarily spiked to recover from the higher indoor temperature that came from setting the thermostat to 89 degrees Fahrenheit, overall energy consumption was still less than having the air conditioners maintain cool conditions. In the case of a conventional central air conditioner, turning off cooling for eight hours a day could yield annual energy savings of up to 11%, the researchers wrote.

But Pigott said how much energy you could save isn’t straightforward. If you’re running your air conditioner at 72 degrees for 16 hours a day and then you turn it off for the eight hours you’re not home, “You don’t necessarily save one-third of your energy cost by turning it off for one-third of the day,” she said.

If the home is better insulated, the air conditioner is more efficient or the climate has less dramatic temperature swings, shutting the system off probably won’t save as much energy.

And while turning off your system is “the most efficient thing to do,” it could result in indoor temperatures becoming uncomfortably warm, Amann said.

“If you don’t have pets or you’re not in a particularly humid climate, you may be able to turn the system off,” she said. “You really just want to think about what the conditions get like in your home if you’re not there and you have the system turned off.”

But a ductless system, such as traditional window units or more advanced mini-split heat pumps, could allow for more flexibility, Amann said. These setups can offer more options for how they can be run than central systems, allowing you to focus on cooling or heating specific spaces instead of the entire home.

“You don’t necessarily need to run every unit in your home,” she said.

It’s important, she and other experts said, to consult with your contractor or HVAC professional about how to best operate your system. For instance, Davis cautioned, more frequently starting and stopping your air conditioning unit could strain the system’s motor.

Think about your thermostat

If you’re concerned about your home getting too warm, you can still get energy savings even though your system isn’t completely off by adjusting your thermostat, Amann said.

Smart thermostats, which can be programmed to suit your schedule, can help do this.

When you’re away from home, Amann said you can probably let the temperature go as much as five to seven degrees higher than what would normally be comfortable for you. A smart thermostat could be set to take into account when you typically come home, so that the indoor temperature is where you would like it to be when you return.

“Certainly when you’re away from home, having those settings can make a big difference, particularly if you’re if away all day for work or if you’re away on vacation,” she said. “You definitely want to make sure you’re setting the thermostat up to allow the heat of the house to get a little warmer than normal.”

Try other ways to keep your home cool

You can help reduce the costs of running your air conditioner by taking other steps to keep your home cool.

Make sure blinds or shades are closed during the hottest parts of the day, particularly if you don’t have updated windows, Amann said. Try to avoid using appliances such as dishwashers, ovens and stovetops or dryers, which can make spaces hotter and more humid and force your air conditioner to work harder, she said.

Using ceiling fans could also allow you to keep your thermostat at a couple degrees warmer and still feel comfortable, Amann said. But remember that “ceiling fans cool people, not rooms,” she said.

“You don’t want to run your ceiling fans all through your house,” she said. “You want to run them in the rooms that you’re in.”