top of page

9 Tips to Lower Summer AC Bills

energy efficiency ac tips nhs brooklyn

If your electric bill skyrockets every summer, your air conditioner is probably to blame. Here are nine tips that will increase your home's energy efficiency and reduce your utility bill.

Tip 1: Use the right size AC for the space you're cooling

AC window units are designed to cool a certain square footage of space. If the room is too big or too small, the AC won't be effective. AC window units use the British Thermal Unit (BTU) rating system, and most are 5,000 to 15,000 BTUs. Every square foot needs about 20 BTUs, plus 600 BTUs per person in the room. Bump that number up by 10% if the room has high ceilings, receives a lot of sunlight, etc. Measure the room dimensions (length x width x height) and add 600 for the number of people who usually use the room to get the number of BTUs your AC unit should be rated for. More is not better, though: an over-sized AC will keep a room cool but it will also leave moisture in it, leaving the room feeling muggy.

Tip 2: Close the windows

An AC unit pulls in warm air from the room; the warm air passes over a refrigerant that absorbs the heat from that air; and the cooled air is blown back into the room while the absorbed heat is expelled out the back of the unit. That's why window AC units should be mounted in a closed window (or piped outside) and why central AC units are located outside of the house. The “inside air” and the “outside air” need to be isolated from each other for the air conditioner to work efficiently. If your windows are open, the heat that gets blown out will just come right back in.

TIP 3: Turn the AC off when you're not home (or get a smart thermostat)

It's a myth that it takes more energy to cool a hot house when you come back home after you're been out than it does to just leave the AC on. In fact, turning the AC off when you're not home and back on when you return can significantly lower your electric bill. If you have to have the home be cool when you come home, get a smart thermostat. They often pay for themselves within the first year and can even increase the value of your home.

TIP 4: Don't set the temperature too low

An AC blows cool air at the same rate, regardless of the temperature it's set to. Setting the temperature very low won't cool the house faster, it will just take longer for the house to reach that temperature, and that will end up costing you more money. Just set the AC to the temperature you want it to reach. If you want the house cool when you come home, get a smart or programmable thermostat.

TIP 5: Close outside and inside doors, and vents

A window unit is only designed to cool a certain amount of square feet, and that's assuming the doors and windows are closed. With a central AC unit, there are usually vents in every room. To reduce energy costs, leave vents open only in rooms that people are occupying and close them in rooms no one is occupying. Close all the doors to these rooms, too.

TIP 6: Add fans to the mix

ACs work better when combined with fans because cool air accumulates in front of the unit or vent and the fan moves it around. To circulate this cool air to the rest of a room quickly (and feel cooler quicker), use a fan. If you use a fan, you can even set your AC to a higher temperature and feel just as cool. If the temperature inside your house is hotter than it is outside, open windows on opposite ends of the house and put fans in each: one blowing out and one blowing in. If you have multiple floors, put the outward-blowing fan in a top-floor window and the inward-blowing fan in a bottom-floor window.

TIP 7: Keep the Unit Clean

It's normal for an AC to drip water due to condensation, but if something goes wrong and the condensation pools, mold and bacteria can grow inside the unit that can then be blown into your home. This type of contaminated air can lead to health dangers like asthma, pneumonia, black mold, and even Legionnaire’s disease. To avoid this situation, clean and service your AC units at the beginning and end of every cooling season. Clean the filters throughout the summer, too. If you run your AC all day every day, change the filter once a month. If you use it less often, change it every three months. If your unit has removable filters, just clean and rinse. If not, you’ll need to replace the filters.

TIP 8: Reduce Heat Sources

Look for and reduce sources of heat and temperature loss in your home. For example, replace single-paned windows with double-paned ones; seal cracks around windows; cover windows with curtains and close them during the day; add insulation to walls facing the sun; turn off computers and laptops when not in use; minimize the use of washers and dryers; and limit time spent cooking on the stove or in the oven.

TIP 9: Address Humidity Issues

Humid air feels hotter than dry air because your sweat can’t evaporate as easily. ACs pull moisture out of the air, but if your AC is leaving excess moisture in the air, a dehumidifier might help and can also prevent certain health threats. They can be pricey to buy and pricey to use, however, so if you must purchase one, check its Energy Star rating.

HAVE MORE IDEAS on how to stay cool on without blowing your budget? Leave them in the comments below!

This article was excerpted from an article, 11 Air Conditioner Blunders to Avoid on Hot Summer Days, dated July 1, 2019, on

bottom of page