Keeping the air conditioning on in extreme heat: Virginia Tech expert shares tips

Melody Warnick

24 Jun 2025

Man suffers from heat in the office or at home — In a heat wave, most Americans rely on electricity to stay cool — but it can stress the power grid. Photo courtesy of Adobe Stock.

As sizzling temperatures hit much of the United States, most Americans keep their cool by blasting the air conditioning or sitting in front of electric fans. But with thousands of customers without power from extreme heat–related outages, can the electric grid keep up with the demand?

“Lighting and air conditioning consume more than 50 percent of electrical energy in commercial and residential buildings — but a much higher percentage in the summer months,” said Virginia Tech expert Saifur Rahman. He offered ideas for keeping the electricity on during a heat wave.

Reset the thermostat. “Raising the temperature setting on thermostats — without causing discomfort — can drop the air conditioning load by 10 to 15 percent. During extreme heat events, setting the thermostat to 80 degrees when no one is home can relieve stress on the power grid.”
Cut the A/C after dark. “In many parts of Virginia, the nighttime temperature usually drops below 70 degrees even when the daytime highs are in the high 80s. It is much better to open the windows at night than to keep the air conditioner running. One can sleep better in cool, fresh air and save electricity.”
Dim the lights. “In commercial buildings, dimming lights in low-usage areas or after hours can reduce electricity demand by 30 percent."
Choose natural light. “In residential buildings, natural light from windows and skylights provides a much better quality light and saves electricity.”
Listen to the power company. “A couple of years ago there was a crisis situation in northern California when the electricity demand was growing very fast on a hot summer weekday afternoon. The local power company asked consumers to cut down on their air conditioner usage, which they did. This avoided a system-wide major power outage.”

About Rahman

Saifur Rahman is the director of the Advanced Research Institute at Virginia Tech, where he is the Joseph Loring Professor in the Bradley Department of Electrical and Computer Engineering. An internationally known researcher in the areas of electrical power, renewable energy, and smart grid, Rahman is the former president and CEO of the Institute of Electrical and Electronics Engineers. Read more about him here.

Interview

To schedule an interview with Rahman, contact Margaret Ashburn in the media relations office at mkashburn@vt.edu or 540-529-0814.