Electric vehicle owners may experience a decrease in driving range during cold weather, compounded by the use of the vehicle’s interior climate control.

Research from AAA said that when temperatures fall to 20° F and the HVAC system is used to heat the inside of the vehicle, the average driving range falls by more than 40%.

The research said that for every 100 miles of combined urban/highway driving, the range at 20° F would be reduced to 59 miles. Colder temperatures may need to charge more often to minimize the chance of being stranded by a dead battery.

Cold weather is not the only factor that can influence driving range. The research also found that when outside temperatures heat up to 95° F and air-conditioning is used inside the vehicle, driving range decreases by 17%. The study found that the use of heat when the temperature is 20° F outside adds almost $25 more for every 1,000 miles when compared to the cost of combined urban and highway driving at 75° F.

AAA tested five electric vehicles, all with a minimum estimated driving range of 100 miles. Real-world driving conditions were simulated using a dynamometer, essentially a treadmill for cars, in a closed testing cell where ambient temperature could be controlled. To determine the effects on driving range, scenarios for cold and hot weather conditions — both when using HVAC and not — were compared to those of driving with an outside temperature of 75° F.

AAA conducted its research along with the Automotive Club of Southern California’s Automotive Research Center (ARC) in Los Angeles. Vehicles were tested using the ARC’s climate controlled test cell and state of the art chassis dynamometer and data logging equipment.