What Winter Does to an EV's Cost per Mile, and How Much of It Is the Heater

In cold weather an EV's efficiency falls by about 8% with the cabin heater off and by roughly 39% in mixed driving at 20°F, according to the Department of Energy. On an illustrative 3.5 miles per kWh at $0.17 a kWh, that moves 1,000 miles from $48.57 to $52.80 without the heater and to $79.63 with it. DOE attributes about two-thirds of the extra energy in cold weather to heating the cabin.

Every price and efficiency below is illustrative. Your electricity rate, your car's efficiency and how cold your winters run are inputs, and the EV vs. Gas Cost Calculator takes them.

Two penalties, not one

DOE's fuel economy in cold weather page gives three figures for electric vehicles:

• "fuel economy can drop roughly 39% in mixed city and highway driving, and range can drop by 41%."
• "About two-thirds of the extra energy consumed is used to heat the cabin."
• "When the cabin heater is not used, EV fuel economy is 8% lower at 20°F than at 75°F."

The page credits the EV estimates to a 2019 AAA study. It does not say the 8% and the 39% came from the same test, so this guide prices them as two separate scenarios and does not try to subtract one from the other.

The starting efficiency should be the EPA rating, which is measured as AC energy drawn from the wall and includes charging losses (EPA). That is the right basis for a bill you pay at the meter.

The worked example

Take 3.5 miles per kWh and $0.17 a kWh. Cost per mile is the price divided by the efficiency. A 39% drop in fuel economy leaves 61% of the efficiency, and an 8% drop leaves 92%.

Scenario	Efficiency	kWh per 1,000 miles	Cost per mile	Cost per 1,000 miles
Mild weather	3.5 mi/kWh	285.7	4.86¢	$48.57
20°F, heater off	3.22 mi/kWh (× 0.92)	310.6	5.28¢	$52.80
20°F, heater on	about 2.14 mi/kWh (× 0.61)	468.4	7.96¢	$79.63

Without the heater, 1,000 cold miles cost $4.23 more than mild ones. With the heater, they cost $31.06 more. Over three winter months at an illustrative 1,000 miles a month, the mild-weather figure is $145.71 and the heater-on figure is $238.88.

Where the comparison goes wrong

1. Using the sticker efficiency all year

A mild-weather figure applied to a winter month understates the bill by $31.06 per 1,000 miles in the example above. Enter a cold-month efficiency for the months it applies to, and keep the mild one for the rest.

2. Treating 20°F as every cold day

DOE's figures compare 20°F with 75°F or 77°F. The page does not publish a figure for 35°F or 5°F. This guide has no sourced figure for other temperatures, so a 35°F day cannot be priced from it. Use your own energy readout for those months.

3. Setting the EV's mixed-driving figure against the gas car's city figure

DOE's 39% is for mixed city and highway driving. Its gas-car figure is for city driving: "roughly 15% lower at 20°F than it would be at 77°F." On an illustrative 27 MPG at $3.19 a gallon, 15% lower is 22.95 MPG, and 1,000 miles go from $118.15 to $139.00, which is $20.85 more. The EV's $31.06 increase is larger in dollars, but the two figures were measured under different driving, so the gap between them is not a like-for-like result. For the full crossover, see the gas price where an EV stops being cheaper.

4. Pricing winter electricity at the home rate when part of it isn't

The cold changes how many kWh a mile takes, not what a kWh costs. Where the kWh comes from does change the bill. At an illustrative $0.45 a kWh on a public network, the 468.4 kWh for 1,000 heater-on miles costs $210.77, against $79.63 at the $0.17 home rate. That is $131.14 more for the same miles. Charging at home vs. the grid works through that split.

5. Counting range as if it were cost

A 41% range drop does not change the price of a mile, but it changes how many miles one charge covers. On an illustrative 250-mile rated range, 41% lower is 147.5 miles. Heater-on cost per mile is already in the table, so range belongs in a separate question: how often you stop to charge, and at what price (see item 4).

What DOE lists for managing it

DOE's page lists these among its tips for plug-in hybrids and EVs: "preheating the cabin while plugged into the charger can extend your vehicle's range," and "using the seat warmers instead of the cabin heater can save energy and extend range." Preheating while plugged in draws wall power at your home rate. This guide does not price either one, because neither the heater's draw nor the seat warmers' is published on that page.

Scope

These are fuel-cost figures only. They exclude the purchase price, insurance, maintenance and depreciation, and they use illustrative prices and efficiencies. They are not a forecast for your car.

Frequently asked questions

How much does cold weather cut EV efficiency?

DOE says fuel economy can drop roughly 39% in mixed city and highway driving at 20°F compared with 77°F, with range down 41%. With the cabin heater not used, it says EV fuel economy is 8% lower at 20°F than at 75°F.

How much of the winter penalty is the heater?

DOE says about two-thirds of the extra energy consumed is used to heat the cabin. It gives the 8% no-heater figure separately, and this guide does not blend the two.

Does cold weather change what a kWh costs?

No. Cold changes how many kWh each mile uses. The price per kWh depends on where you charge, so a winter mile costs more at both home and public rates.

Do gas cars lose efficiency in the cold too?

Yes. DOE says a conventional gasoline car's mileage is roughly 15% lower at 20°F than at 77°F in city driving, and it can drop as much as 24% on short trips of 3 to 4 miles.

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This guide is informational only and is not professional financial advice. Last reviewed: October 2026.