Your A/C: Leave it on or off when you're not home?

Posted at 2:25 AM, Jul 07, 2016
My family and I recently headed out of town for the weekend, and my husband and I debated turning the air conditioning off or leaving it on but raising the temperature on the thermostat.
We ended up leaving it on and raising the temp. From an energy-saving perspective, we’d have been wiser to turn it off completely.
“Air-conditioning systems run most efficiently when they are running at full speed,” Jennifer Thorne Amann, MES, buildings program director for the American Council for an Energy-Efficient Economy (ACEEE), recently told Rodale’s Organic Life. Rather than charging your A/C unit with performing a number of short cool-downs during the day, Amann said one big cool-down upon returning home will ultimately save more energy and better dehumidify your home to boot.
If you have a programmable window unit or central air thermostat and are worried about your home getting too warm if you turn the A/C off altogether, set the temperature as high as you can. The ACEEE estimates that air conditioners use three to five percent less energy for every degree you raise the thermostat.
Other simple ways to save energy and money while keeping cool include:
1. Replace or clean A/C filters on a monthly basis
According to “Dirty air filters are the No. 1 cause of air conditioning breakdowns and they cost about 7 percent more in energy costs (or about $45 a year) in hot climates.”
2. Use a ceiling fan in conjunction with your A/C
While a ceiling fan won’t lower the temperature of a room, feeling the air move across your skin will help you feel cooler. Just be sure to turn the fan off when you leave a room to avoid wasting energy.
3. Create a draft
If it’s cool enough, try turning off the A/C and creating “crosswinds” across your house instead. Open windows on opposite sides of the house just enough to create a draft. Avoid opening them too much, as the breeze won’t pull through if the window is opened all the way. Rodale’s Organic Life suggests experimenting with windows on different levels of your house to see which create the best crosswind.
4. Upgrade your air conditioner or thermostat
Upgrading to a newer, energy-efficient air conditioning unit can help keep your home cooler and cut costs at the same time. Likewise, investing in a programmable thermostat can allow you to set different temperatures throughout the day. “Smart” thermostats like the Nest retail for around $220, and work to adjust temperatures automatically, can be adjusted remotely from your phone and will tell you when you hit a temperature that saves energy. Pretty smart, indeed!