When Is the Best Time to Run the Air Conditioner?
3 pros!
Follow these tips to save energy and get the most out of your A/C in the summer heat.
Talk with your HVAC specialist if your A/C doesn't cool as well as it should. (Photo courtesy of Angie's List member Robert N. of Berea, Ohio)
Dear Angie: What is the best way to run air conditioning? Is it better to keep the A/C running all day at, say, 75 degrees? Or should I turn it off all day and then when I come home from work, turn it on? Is one more expensive than the other? — Sandy M., Battlement Mesa, Colorado.
Dear Sandy: Air conditioners are designed to maintain a constant temperature in the home, so the most efficient way to run an air conditioner is to let it keep going and maintain those even temperatures, rather than trying to catch up. The cooler you can keep the house, the less the unit has to work.
The ideal way to run your air conditioner is to have a programmable digital thermostat. You can set it to a desired temperature based on the time of day and even the day of the week. With this “setback” method, you want to keep your setback temperature and comfort temperature within 5 degrees of each other. So, for example, you can have the thermostat programmed to run automatically at 80 degrees during the day while you’re at work, and then have it set to drop to 75 degrees just before you return home. That will maintain a comfortable indoor air temperature and save money on your energy bills.
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"The cooler you can keep the house, the less the unit has to work." — Angie Hicks
Smart thermostats help control temperature
Another relatively new product to help control your indoor air temperature is a Wi-Fi or smart thermostat, which you can control online from any device connected to the Internet — such as a computer or smartphone — and you can adjust anytime you choose.
You should avoid a setback variance of more than 5 degrees, or turning the air conditioner off before you leave and on again when you return. The problem with that is the system will have a hard time catching up to reach that desired temperature, especially if it’s an extra-hot day. The unit will work much harder to satisfy the thermostat setting, which will require more energy and ultimately defeat the cost-savings goal. By letting the unit run, it will cost less overall to operate and your home will almost certainly be more comfortable.
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Whether you turn the unit off and on, or run it all day, it likely won’t damage your A/C, provided it’s in good shape and maintained on a regular basis. Most reputable heating and cooling specialists offer low-cost preventive maintenance programs to keep your system in good working order. A good heating and cooling contractor can also offer advice on the best way to keep your home comfortable and energy efficient. Of course, one simple but important way to keep your system working well is to inspect and change your air filters regularly.
Angie Hicks is founder of Angie’s List. Have a question for her team? Email askangie@angi.com or tweet to #AskAngie. Follow her @Angie_Hicks.
What times work best for you to run the A/C in summer? Share your experiences in the comments below.
Editor's note: This is an updated version of an article originally published on Sept. 4, 2012.
