If it seems like high temperatures are here earlier (and getting hotter) every year, that’s because they are: Many of us have already been running our air-conditioners for weeks. But do you know how to squeeze the most efficiency out of your air- conditioner? What about the best way to keep electric bills down? This year the average summer electric bill in the U.S. is projected to be $788, which is 8.5% higher than 2025. Air conditioners are among the most electricity-intensive appliances in homes.

While it might seem like your air-conditioner is adding cold air to the room, technically it’s taking the heat inside your home and moving it outside. Essentially, hot air runs over cold coils filled with refrigerant, a chemical that gets very cold. The coils collect the heat and moisture (causing the condensation that drips from your unit), and blows them outside. Then a fan blows whatever is left back into the room.

In general, standard residential air-conditioning units are engineered to lower the indoor temperature by a maximum of 20 degrees compared to the outside air. This is easier is drier than humid climates.

After heat pumps and central air-conditioning, window units are considerably more efficient than portable units, those robot-like appliances that sit on the floor and have large hoses venting to the outside. But there are lots of reasons someone may opt for a portable unit, such as having the wrong type of windows, building rules or safety laws that prohibit window units.

When air-conditioners cool down a room, they are also removing moisture from the air — in other words: dehumidifying. This means that the condensation, or water, that builds up inside the unit needs to go somewhere. So you should install the unit with a slight downward tilt, to help that water drip outside, instead of inside your home (and to avoid mold). But always check your specific window unit’s instruction manual; there are some models that already have an angled internal drip pan.Most newer air conditioner brackets which hold the unit in place, allow you to adjust the frame to various positions, so that you can fine-tune the angle to work with your specific windows.

Then there is the filter. If filters are dirty, not only are they less efficient at cooling you down, but they can also make allergies worse.Most window air-conditioners, portables and mini-splits have washable mesh filtersthat you can rinse out and clean yourself. Central HVAC systems have disposable filters that can last up to three months, but factors like pets, or nearby wildfires, can quickly clog them up and force you to swap them more regularly. If you’re using fans in your house, it’s also a good idea to clean those about once a month.

If you’re leaving your house for several hours on a hot day, experts recommend that you leave your air-conditioner on, set to around 78 degrees, even when you’re not home. It turns out that leaving the air-conditioner at around 78 during the day uses considerably less energy than leaving it off and then aggressively cooling everything back down when you return home.

Cooler temperatures are only half of the equation when it comes to actually feeling cool. Humid air makes it more difficult for sweat to evaporate which is why damp summer days feel hotter. If your air-conditioner is having trouble keeping up with the high temperatures and the humidity, you need a dehumidifier.

Even if your AC does a decent job of dropping the actual temperature, it could still leave the room feeling clammy, dank, and, well, generally unpleasant. Most people think of a dehumidifier as an appliance for drying out a damp basement. But technically speaking, it’s more similar to an air-conditioner than people might realize.

While window fans are not a realistic replacement for an air-conditioner, especially in very hot and muggy climates, they are a great alternative in mild and dry summer weather.    They have also come a long way since traditional box fans — they take up less room and can simultaneously pull hot air out and draw fresh air in. But if you only have an old fashioned box fan, and the temperatures are relatively mild, facing your fan outward during the day and inward at night is ideal. Unlike room fans, however, window fans require an open window, so they’re not a good alternative to use alongside air-conditioners as you’ll lose all your cooled air.

Room fans on the other hand, can help spread your air-conditioned air more evenly around your home. If you have ceiling fans those can also help circulate air to make everything feel cooler. The general rule for ceiling fans is to run them clockwise in the winter, which pulls cold air up, and counterclockwise in the summer, to push cool air down.