7 Air-Conditioner Mistakes That Waste Energy and Money

Whether you have a window unit or an HVAC system, our expert-recommended air conditioner tips will help you keep your home cool and comfortable all season long.

Warmer weather is upon us at last, which calls for delicious meals on the grill, weekends at the local farmers markets, and, inevitably, cranking the air conditioner. Summer 2021 is predicted to be hotter than average, so making sure your air conditioner is running smoothly will be crucial to a cool, comfortable home this season. If your air conditioner isn't installed, maintained, and used properly, you could be wasting a lot of energy, money, and time. See what mistakes you could be making when it comes to your air conditioner, then follow our expert-vetted tips to get the most out of your air conditioner (and your summer).

residential outdoor air conditioner unit
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1. You wait until summer to check on your AC.

Don't wait until your air conditioner breaks down at the height of summer to start thinking about upkeep. A little preparation before temperatures soar can go a long way in preventing AC problems throughout the warm season. "Do as much as you can to prepare your AC now so that you can avoid costly repairs in the coming months due to lack of proper maintenance," suggests Mark Dawson, chief operating officer at One Hour Heating & Air Conditioning. He also notes that AC companies tend to be busiest between June and August, so it could be difficult to schedule a tune-up when summer is in full swing. Think ahead and start preparing early to ensure your AC is in top shape before summer hits.

2. You don't have a programmable thermostat.

Constantly readjusting the temperature settings can put extra stress on your air conditioner. A programmable thermostat takes the hassle out of managing your home's temperature throughout the day and can cut down on cooling costs. Plus, it can help an older unit run more efficiently. "You can extend your old AC’s lifespan by carefully programming it and decreasing the amount of time it needlessly runs," Dawson says. Schedule temperature changes at night or at times when you're not at home so the AC isn't running unnecessarily.

3. You're neglecting the air filter.

Air conditioners work by sucking in air and passing it over a continuous liquid-to-gas-to-liquid chemical reaction. That reaction forces the air around it to absorb its heat, thus lowering its temperature. With all that movement, it's inevitable that dust, dander, and allergens get stirred up. The filter is designed to catch any nasty stuff accumulated in the air.

However, as it grabs more and more particles, the filter can become clogged. That means the air conditioner has to work much harder to cool a room. It can also force dust into the room, which you definitely don't want. "Clogged air filters can damage your air conditioner system's parts and result in costly repairs," says Lenny Cipolla, an owner of Florida-based HVAC service and repair company Southern Coast Services.

You should clean the filter on a central air conditioning unit about once a month. The filter location will vary based on your model, but be sure to turn off the power before you do so. A window unit likely has a warning light indicating when it's time to clean the filter. And cleaning an air conditioner filter is pretty easy. Simply suck up any loose debris up with a vacuum, then soak the filter in a mixture of equal parts hot water and white vinegar. Give it a rinse, let it dry, and you should be good to go!

4. You installed it in a sunny spot.

For window AC units, location is everything. If your air conditioner is located in an especially sunny place, the unit will have to work much harder to cool the air, which could cost you money over time. If possible, install it in a shady spot. For outdoor units, make sure the space around it is clear: No trees, shrubs, flowers, or structures should block the airflow.

Another common installation problem is not sealing the window properly. If there's space around the air conditioner, you'll let in hot air. Make sure that the fold-out shield on a window unit blocks as much air as possible. Then you can look into weatherstripping to seal up any gaps.

5. Your AC unit is surrounded by appliances.

Most air conditioners have sensors that let you pick a temperature and prompt the unit to cycle on and off to maintain that temperature. But these can be unintentionally tricked. Make sure there are no appliances that give off heat near your air conditioner. This includes lamps, kitchen appliances like refrigerators, and home electronics like televisions. Those items will raise the temperature in their immediate area and fool the air conditioner into working harder—and thus less efficiently. Consider using blackout curtains in the room with your AC unit.

"Close the blinds or drapes on the sunny side of your home during the hottest part of the day to naturally lower the inside temperature," says Ted Noonan, owner of Noonan Energy in Massachusetts. "Avoid cooking meals that involve the oven, which can increase the temperature in your home and force your unit to work harder."

6. You use it on mild days.

Frankly, we all probably use our air conditioners more than necessary. These units use a lot of energy, making them expensive to run. It could cost you as much as $25 per month per unit to run half of each day.

If it's only mildly hot outside, or if you're not in the same room as the air conditioner, turn it off. Fans, especially ceiling fans, are a good alternative, as they do a great job of circulating air. Plus, a ceiling fan costs only $1.50 per month for the same usage. And the less you use it, the longer your air conditioner will last.

7. You ignore preventive maintenance.

For smaller window AC units, proper location and air filter cleaning will take you through the life of the system. But for large HVAC units, more maintenance might be needed. "At a minimum, air conditioning condenser coils should be cleaned at least twice a year," says Richard Ciresi, owner of an Aire Serv heating and cooling franchise. "It is best to clean the condenser coils before starting the system for the season and again when the weather starts to get hot for prolonged periods of time." The condenser coils are located on the exterior box of your HVAC system. To clean them, first turn off the power at the outdoor shutoff, then use a coil brush or vacuum to remove debris. Spray with a hose or wash with coil cleaner as needed.

Scheduling a yearly tune-up with an air conditioning technician can also help prevent minor issues from turning into major problems, Dawson says. A professional will likely test the unit and check for common maintenance issues including dirty coils, old air filters, and clogged condensate drains. They can also lubricate the system's parts and recharge the refrigerant to keep your unit running at peak performance.

There are few feelings of relief so perfect as coming in from a hot, humid summer's day to a crisp, air-conditioned house. But it's important to remember that these appliances won't simply take care of themselves. Take care of your AC unit with our expert tips, and it'll keep your family cool all season long.

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