Duke Energy asks NC customers to limit power during heat wave. Here’s what to do

Duke Energy is urging customers to limit their electricity usage as temperatures in North Carolina approach triple digits.

According to an extreme heat warning from the National Weather Service (NWS) on Tuesday morning, heat index values in the Triangle could reach as high as 111 degrees.

In Charlotte and much of western North Carolina, temperatures are expected to reach the upper 90s, with heat index values in the 105-108 degree range, according to an extreme heat warning from the NWS.

Both warnings will remain in effect until Wednesday at 8 p.m.

Extreme heat means more customers are likely to use their air conditioning units, but excessive strain on the power grid could lead to blackouts, similar to the ones that occurred on Christmas Eve 2022.

Record-low temperatures and an increased demand for heat led to more than 100,000 Duke Energy customers in the Charlotte area losing power, The Charlotte Observer previously reported.

Here are some ways to conserve energy, including the best thermostat setting for the summer months.

How to protect the power grid during a heat wave

Duke Energy provided the following tips on how customers can help protect the power grid:

• Set your thermostat to the highest comfortable temperature.

• Delay laundry and other appliance use until evening or early morning.

• Limit oven and stovetop use to avoid heating up your home.

• Grill outside to reduce indoor heat and energy use.

• Turn off unused lights, appliances and plug-ins.

Best thermostat temperature in summer

The ideal thermostat setting varies by climate and personal comfort, according to the U.S. Department of Energy. However, raising it by up to 10 degrees for eight hours a day can cut energy costs by as much as 10% annually, the Observer reported.

“The smaller the difference between the indoor and outdoor temperatures, the lower your overall cooling bill will be. You can easily save energy in the winter by setting the thermostat to around 68°F to 70°F while you’re awake and setting it lower while you’re asleep or away from home,” the agency’s website says.

“In the summer, you can follow the same strategy with central air conditioning by keeping your house warmer than normal when you are away, and setting the thermostat to a setting as high as is comfortable for you when you are at home and need cooling and to ensure humidity control if needed.”

When you first turn on your air conditioner, avoid setting the thermostat lower than usual – it won’t cool your home faster and may actually increase your energy costs,.

Best thermostat setting for air conditioning

The recommended thermostat setting for the summer season is 78 degrees, according to the N.C. Department of Environmental Quality (NCDEQ).

You can also use fans and light bedding, turn off unused lights and electronics, seal gaps around pipes and cracks and switch to energy-efficient LED lighting to conserve energy during the warmer months, according to NCDEQ.

How to stay safe during a heat wave

Here are some ways you can stay safe in the heat, according to Ready.gov, an online resource for information on preparation for natural disasters:

• Never leave people or pets in a parked car.

• Stay cool at home with air conditioning or by taking cool showers and wearing lightweight, light-colored clothing.

• Limit oven use to help keep indoor temperatures lower.

• If you’re outside, find shade, wear a wide-brimmed hat and avoid peak midday heat.

• Stay hydrated by drinking plenty of fluids throughout the day.

• Avoid strenuous outdoor activities during the hottest part of the day, if possible.

• Check on others, including older adults, neighbors and family members.

• Protect pets with shade, fresh water and by avoiding hot pavement.

This story was originally published June 24, 2025 at 11:57 AM with the headline "Duke Energy asks NC customers to limit power during heat wave. Here’s what to do."

Evan Moore

The Charlotte Observer

Evan Moore is a service journalism reporter for the Charlotte Observer. He grew up in Denver, North Carolina, where he previously worked as a reporter for the Denver Citizen, and is a UNC Charlotte graduate.