How winter weather hurts fuel efficiency — and what you can do about it
It seems inevitable: the colder it gets, the more fuel your vehicle uses. But there’s hope! You can make smart choices to lessen winter’s impact.
Cold weather means higher fuel consumption
The U.S. Environmental Protection Agency (EPA) estimates that a drop in temperature from 24°C to 7°C can increase fuel consumption in urban commutes by 12 to 28%.
Why your vehicle uses more fuel in winter
Aerodynamic resistance is greater in the winter
Cold, dry winter air is 11% denser than warm, humid summer air. The increased resistance increases highway fuel consumption by about 1.3%.
The average wind speed is higher in the winter too, which also increases aerodynamic resistance and fuel consumption.
Winter weather creates difficult driving conditions
You’ll encounter rougher roads when driving in winter. Your engine must work harder to overcome the increased rolling resistance these obstacles create.
Snow and ice also increase wheel slippage, which means higher fuel consumption. Fuel consumption can increase 7 to 35% because of poor winter road conditions alone, according to U.S. EPA data.
Winter gas normally has lower energy density
Gasoline composition is seasonally and geographically adjusted based on historical temperature data. A litre of winter gas has less energy than a litre of summer gas, typically in the range of 1.5 to 3%. Diesel fuel is affected similarly.
Winter driving taxes the vehicle’s electrical system
Other than the use of air conditioning, your vehicle’s electrical loads are normally higher in cold weather. This is due to greater demand from heating, defrosting, head lights and interior lights, heated seats, heated mirrors and increased use of the windshield washer pump.
The energy for these comes from the vehicle’s electrical system, which gets its power from the engine.
How to reduce winter’s toll at the pump
By following these tips, you can lessen the impact of winter weather on your fuel consumption and carbon dioxide (CO2) emissions.
Don’t idle to warm up!
Idling for more than 30 seconds has no benefit for the vehicle. Ten minutes of idling burns 0.25 to 0.50 litres of fuel and emits 600 to 1,200 grams of CO2, depending on the vehicle and conditions.
Driving for a few minutes is the most efficient way to warm the engine, drivetrain and the cabin.
Keep tires properly inflated
Tire pressure drops when the temperature drops, and driving a vehicle with tires under-inflated by 56 kilopascals (8 pounds per square inch) can increase fuel consumption by up to 4% and reduce the life of the tires by more than 10,000 km.
Measure your tire pressure at least once every month, and more often during seasonal changes, to ensure a proper level of inflation.
Use a block heater
Block heaters warm your engine in advance, which reduces fuel consumption and emissions. For best results, put your block heater on a timer, set to turn on no more than 2 hours before you start the engine.