AAA Study: Extreme Summer Heat Reduces Electric Vehicle Range and Efficiency

If it seems like your electric vehicle’s range melts away more quickly in the scorching summer heat — you’re right. A new AAA study shows that extreme temperatures reduce efficiency and range for EVs and hybrids. 

Key Facts 

• Study Finding: EVs experience a 10% decrease in efficiency when temperatures reach 95 degrees, compared with performance at 75 degrees. 

• Range Impact: EVs lose approximately 8.5% of driving range at 95 degrees. 

• Impact on Hybrids: Hybrid vehicles experience a 12% decrease in fuel efficiency during extreme heat. 

• Primary Takeaway: While winter temperatures remain the biggest challenge for EV efficiency, summer heat can also significantly reduce vehicle performance and operating efficiency. 

• Consumer Guidance: AAA Northeast recommends tire maintenance, reduced highway speeds, cabin preconditioning, eco mode use, strategic parking and smart charging practices to maximize efficiency. 

While cold temperatures have the greatest impact on efficiency and range, hot weather plays a role, too. The AAA study found that EVs experience a 10% drop in efficiency and an 8.5% loss of range in 95-degree temperatures, compared with their performance in 75-degree temperatures. For example, an EV with 250 miles of range may have just under 230 miles at 95 degrees. Additionally, hybrids experience a 12% decrease in fuel efficiency. 

AAA offers the following tips to maximize EV efficiency and range: 

• Check your tire pressure. Like any vehicle, underinflated tires waste energy and reduce efficiency. 

• Remove roof racks. Removing roof racks can improve range by reducing aerodynamic drag. Extra weight in the trunk or cargo area can also reduce range. 

• Don’t speed. Higher speeds significantly reduce range, especially over 70 mph, when aerodynamic drag increases rapidly. 

• Precondition the cabin while the vehicle is plugged in. Use seat ventilation instead of relying heavily on the air conditioning. Setting the temperature to 78 degrees instead of 70 degrees can significantly reduce energy use while keeping the cabin comfortable. Climate control removes humidity, so higher temperatures will still feel cool. 

• Use eco mode. Depending on your vehicle’s settings, eco mode may reduce energy consumption by softening throttle response, optimizing regenerative braking and reducing auxiliary power use.  

• Park in the shade when possible and use a windshield sunshade to reduce cabin heat. Before getting into a very hot vehicle, open the doors briefly to let trapped heat escape.  

• Evaluate charging access and energy pricing. EV operating costs depend heavily on electricity rates and where charging occurs. Home charging can help manage seasonal cost swings compared to frequent public charging. When using public charging stations, charge at a lower rate when possible. Level 1 and Level 2 charging may help preserve long-term battery health compared to frequent use of Level 3 DC fast charging.  

• Don’t let a hybrid run on empty. Running a hybrid on empty can severely damage the internal combustion engine and electric drivetrain. Hybrid owners looking to save money on fuel should plan to fill up before nearing empty to allow time to find the cheapest gas station.  

Jillian Young

Based in Rhode Island, Jillian Young is AAA Northeast’s director of public relations. She regularly appears in local TV, radio and print media to discuss traffic safety, travel, insurance and more.