Save on Winter Fuel Costs
Feb. 5, 2015
Cold weather and winter driving conditions can reduce your car's fuel economy significantly, but there are things you can do to lessen the effects.
Old Man Winter can create more mischief than just icy sidewalks and snow-packed roads. Winter can also hit you in the pocketbook when it comes to driving. Consider this: on a short drive through the city, a conventional car's gas mileage is about 12% lower at a winter temperature of 20°F than it is at 77°F in warmer months. Mileage per gallon (MPG) can drop as much as 22% for very short trips.
The effect on hybrid vehicles is even worse; their fuel economy can drop 31%-34% in winter temperatures.
Why is winter fuel economy lower?
Cold weather affects your vehicle in more ways than you might expect:
- Warming up your vehicle before you start your trip lowers your fuel economy—idling gets 0 miles per gallon.
- It takes longer for your engine to reach its most fuel-efficient temperature. This affects shorter trips more, because your car spends more of your trip at less-than-optimal temperatures.
- Window defrosters, heater fans, and heated seats use additional power.
- Colder air is denser, which increases aerodynamic drag on your vehicle, especially at highway speeds.
- Tire pressure decreases in colder temperatures, increasing rolling resistance.
- Battery performance decreases in cold weather, making it harder for your alternator to keep your battery charged. This also affects the performance of the regenerative braking system on hybrids.
- Engine and transmission friction increases in cold weather due to engine oil and other drive-line fluids being colder.
- Winter grades of gasoline can have slightly less energy per gallon than summer blends.
In winter weather that's severe, your MPG can drop even further:
- Icy or snow-covered roads decrease your tires' grip, wasting energy.
- Safe driving speeds on slick roads can be much lower than normal, further reducing fuel economy, especially at speeds below 30 to 40 mph.
- Using four-wheel drive uses more fuel.
What can I do to improve my fuel economy in cold weather?
While you can't completely mitigate cold weather's effect on your fuel economy, you can do some simple things to help your gas mileage and the costs you pay:
- Minimize the time you spend idling your car to warm it up. Most manufacturers recommend driving off gently after about 30 seconds. The engine will warm up faster being driven, which will allow the heat to turn on sooner, decrease your fuel costs, and reduce emissions.
- Don't use seat warmers or defrosters more than necessary.
- Check your tire pressure regularly.
- Use the type of oil recommended by your manufacturer for cold weather driving.
- Remove accessories that increase wind resistance, like roof racks, when not in use.
- If you drive a plug-in hybrid electric (PHEV) or all-electric vehicle (EV), preheating the cabin while plugged into the charger can extend your vehicle's range.
- If you drive a PHEV or EV, using the seat warmers instead of the cabin heater can save energy and extend range.
- Combine trips when possible so that you drive less often with a cold engine.
For more information, visit fueleconomy.gov's Fuel Economy in Cold Weather page.
- Kathryn Ruckman, National Renewable Energy Laboratory
- For more information:
- Clean Cities Technical Response Service Team