Winterize Vehicles to Save Energy
Dec 05, 2015 03:57PM
We get worse gas mileage when it's cold because winter driving conditions reduce fuel economy significantly. On chilly days when temperatures drop to 20 °F or lower, expect to see up to a 12 percent hit on fuel economy for short city trips. During very quick trips, traveling only three to four miles, fuel economy could dip as much as 22 percent. This due to several factors. Cold temperatures increase the time it takes the vehicle to warm the cabin, engine, drive‐line fluids and other components up to fuel‐efficient operating temperatures. Also, cold fluids increase the friction on the engine and transmission, which can reduce fuel economy.
Myth: To warm up the engine and vehicle cabin in the wintertime, we should let the engine run for several minutes before driving.
Truth: Most manufacturers recommend driving off gently after about 30 seconds of idling. In fact, the engine will warm up faster when driving. Idling can use a quarter to half a gallon of fuel per hour, and even more fuel if the engine is cold or accessories like seat heaters are on.
Also keep in mind that winter gasoline blends in cold climates have slightly less energy per gallon than summer blends. This is because refineries alter the chemical makeup of gasoline to allow it to evaporate more easily in low temperatures, ensuring proper engine operation.
Aerodynamic drag is another consideration. In simple terms, cold air is denser than warm air, so when temperatures drop, wind resistance increases slightly. This requires a little more power from the engine to drive at a given speed. The effects of aerodynamic drag on fuel economy are most significant at highway speeds.
Winter Fuel‐Saving Tips: Park in a warmer place like a garage that traps heat to keep the initial temperature of your engine and cabin higher than it would be outside in the elements. Avoid using seat warmers more than necessary, as they require additional power.
For more information on how to improve fuel economy, visit FuelEconomy.gov.