Cold weather can reduce your fuel economy drastically, but there are ways to mitigate the impact.
A cold engine, driveline and battery pack have more friction, use more fuel and reduce the efficiency of hybrids’ regenerative braking, said Brian West, a development engineer at Oak Ridge National Laboratory in Tennessee.
West compared fuel consumption on the 20 degree Fahrenheit and 75 degree Fahrenheit cycles of the test the EPA uses for fuel economy ratings.
The fuel economy of conventional gasoline vehicles fell 12 percent to 22 percent, with the biggest decrease on short trips of 3-4 miles. Hybrids fell 31 percent to 34 percent.
“The majority of the hit is from more viscous fluids before the drivetrain warms to its optimum temperature,” West said. “The hit on hybrid fuel economy is more severe because cold batteries are less efficient recapturing energy from braking.
“The impact is greater for both types of vehicles on shorter trips” that don’t give fluids and batteries time to reach operating temperature.
Here are some cold-weather tips from FuelEconomy.gov:
• Park in the warmest available spot. An enclosed garage is best.
• Combine several errands into one trip so the drivetrain has time to warm up.
• Don’t use seat heaters and defrosters longer than necessary.
• Don’t let your car sit idling to warm up. The most efficient technique is running the engine for 30 seconds, then driving off gently. The engine warms up faster while being driven.
• Plug-in hybrids benefit from preheating while still plugged in, before you start driving.
• Plug-in hybrids are more efficient if you use the seat and steering wheel heaters more than heated air. It’s fine to keep them running all the time in a plug-in.
• Keep your tires properly inflated.