In 20-degree weather, driving range can plummet by 41 percent from running HVAC

BOISE – (February 7, 2019) – Battery electric vehicles (BEV) are environmentally friendly, cut down on long-term ownership costs, and offer smoother acceleration. But the extreme temperatures found in places like Idaho could require BEV owners to plan ahead in order to prevent a roadside mishap due to unexpected power loss, and to avoid unnecessary delays and charging costs.

According to AAA’s latest research, using the air conditioner in 95-degree weather can reduce an electric vehicle’s driving range by 17 percent. Even more astonishing, BEV drivers who use their heat in 20-degree weather can expect their vehicle range to drop by an average of 41 percent.

“Using the vehicle’s HVAC system to combat severe temperatures is important to guard against heat stroke and hypothermia,” says AAA Idaho public affairs director Matthew Conde. “But because cold weather can chop an electric vehicle’s range nearly in half, it’s important for drivers to consider the seasonal adjustments they may need to make to stay safe on the road.”

When temperatures peak, and especially when they plummet, AAA encourages BEV drivers to plan ahead by building in additional pit stops to recharge, and by bundling trips. Another way to reduce battery drain is by pre-heating or pre-cooling the vehicle while it is still connected to the charger.  Finally, electric vehicle owners can stabilize vehicle temperatures by keeping them in a garage.

“With advance preparation, the average commuter who drives 40 miles or less should be largely unaffected by the weather,” Conde said. “But for longer road trips, there could definitely be some range anxiety.”

The weather doesn’t just drain the vehicle’s battery; according to AAA’s research, it also depletes a traveler’s time and money. On average, an outside temperature of 20 degrees imposes an additional cost of $24.27 for every 1000 miles.  An outside temperature of 95 degrees results in an additional expense of $7.94 for every 1000 miles.

“The time loss due to extra charging may be more substantial than the price tag,” Conde said. “It’s clear that the more charges you can avoid, the better.”

AC level 1 charging can fully restore a battery in 8 to 13 hours. Level 2 charging is a faster approach, but it requires a dedicated circuit and a special charging station in one’s garage, carport, or driveway at a cost of $200 to $1,500 per installation.  Finally, the public level 3 charging stations can restore the majority of range in just 45 minutes, but they also carry a higher cost per kilowatt hour.

AAA tested five commonly available battery electric vehicles as part of its research. Each vehicle was tested at 75 degrees – the temperature established by the Society of Automotive Engineers, to obtain baseline results.  Then, vehicles were tested in 20-degree and 95-degree external temperatures, with and without HVAC use.

When the HVAC was not deployed, driving range under cold conditions dropped twelve percent, and under hot conditions, range dropped just four percent. When the heating and cooling systems were used, the battery drain was much more pronounced.

“There are more than 16,000 charging stations across the U.S., and electric vehicle technology is constantly improving, so some day, range may no longer be an issue,” Conde said. “In the meantime, we want electric vehicle owners to be prepared, especially in the rural, cold conditions that they may periodically encounter in Idaho.”