When climate control wasn't in use, estimated driving range for electric vehicles was moderately impacted by hot and cold temperatures when compared to testing conducted at 75°F. Climate control use resulted in considerable reductions in driving range.
These results mean that on average, for every 100 miles an EV can drive at 75°F, it can drive 83 miles at 95°F with the air conditioning on, and just 59 miles at 20°F with the heater running. For example, an EV with a 240-mile range might be able to drive round-trip between Los Angeles and Palm Springs on a full battery in mild weather, but with the air conditioning engaged in a 95°F heatwave, its range would be reduced by about 40 miles and the driver would need to recharge at least once.
Gasoline-powered cars lose range, too1
Like any car component, the high-capacity lithium-ion batteries in an EV have a temperature range that they work best within. As temperatures fall, diffusion, conductivity, and reaction rates inside the battery cells drop. This leads to increased voltage perturbation and heat generation, consuming energy that could've otherwise propelled the vehicle. At very low temperatures, extra energy may be used to heat the battery to prevent damage.
Similarly, at elevated temperatures, a cooling system must run to keep the battery from overheating. This also uses extra energy and thus effectively reduces driving range. Aggressive driving results in more heat generation, increasing battery cooling demands.
The two biggest decreases in EV driving range in AAA's testing came when climate control was turned on. As anyone who's ever paid a utility bill during a hot summer or cold winter knows, air conditioners and space heaters use a lot of electricity.
Using the heater at below-freezing temperatures produced by far the largest drop in range. Unlike gas-powered vehicles, where the engine produces heat as a byproduct of burning fuel and this can be used to heat the cabin, EVs have to run a separate electric heater.
Embrace efficiency (and savings)
The impact of the weather is more keenly felt by EVs because charging their batteries takes longer than refilling a gas tank, but they have the advantage of being much more cost-efficient because electricity is cheaper per mile than gasoline. AAA’s study found that driving an EV 1,000 miles with the A/C on when it’s 95°F outside adds about $8 more in electricity costs than driving at 75°F. By comparison, a gasoline vehicle rated at the U.S. average of 23.6 mpg would require an additional $21 in gasoline (and that's with the relatively low gas price of $2.43 per gallon).
Check the forecast ahead of a long-distance trip to see if you'll be traveling in very hot or cold weather. If so, plan for more frequent stops to charge, and map out the charging stations you'll be using and the distance between them.
Pre-heat or pre-cool before unplugging
Make time to warm up or cool down the inside of the vehicle while still connected to the charger. This lets the battery save its charge for driving.
Dial the climate control back a little
There's no avoiding using the heater or air conditioning in freezing or sweltering weather, but if you're trying to stretch out your driving range, use them modestly. Just like an indoor thermostat, it's more efficient to set the climate control to a comfortable temperature and dress appropriately than to run it on blast.
Park in a garage, if possible
Leaving the vehicle indoors can help keep the cabin temperature stable between drives, instead of letting it match the extremes of the weather outside.
1 Lohse-Busch, H., Duoba, M., Rask, E., Stutenberg, K. et al., "Ambient Temperature (20°F, 72°F and 95°F) Impact on Fuel and Energy Consumption for Several Conventional Vehicles, Hybrid and Plug-In Hybrid Electric Vehicles and Battery Electric Vehicle," SAE Technical Paper 2013-01-1462, 2013, https://doi.org/10.4271/2013-01-1462.
Information taken from "Icy Temperatures Cut Electric Vehicle Range Nearly in Half," American Automobile Association, Feb. 7, 2019, and "AAA Electric Vehicle Range Testing," American Automobile Association, February 2019.