When to Plug in Your Block Heater

By Lori Straus

Although this winter hasn’t felt like much of a winter for those of us in southern Ontario, winter always includes temperatures below -10 Celsius for the entire province. And remember last winter? For the western half of Canada, from the Upper Great Lakes to the Pacific coast, February 2019 saw the lowest temperatures in at least 70 years. In Toronto, one year’s worth of snow fell in the first two months of 2019, and Torontonians had only 10 days without precipitation during that time. For us in Ontario (and likely the rest of the country), it felt like the winter that wouldn’t end and left a lot of us idling are cars to warm them up. A block heater, that wondrous accessory on cold winter days, can help reduce that warm-up time.

A Few Words About Idling

You already know that idling your vehicle is bad for the environment. In fact, Natural Resources Canada (NCRC) says that an average-sized vehicle with a 3 L engine burns more than a quarter litre of fuel after 10 minutes of idling. The NRC estimates that if all Canadians reduced idling by only three minutes a day— regardless of the season—we would all save about 630 million L of fuel and 1.4 million tonnes of CO2 every year.

In addition, idling your vehicle for 10 minutes doesn’t warm up your entire vehicle. The only way to effectively warm up the vehicle is to drive it. Because today’s cars have computer-controlled engines, you shouldn’t need more than two to three minutes to warm up a vehicle for driving, if that.

Using a Block Heater

Although vehicles sold in Canada must start at-30°C, experts recommend plugging in your block heater when temperatures dip below-15°C. A block heater is attached to your engine block and keeps the coolant warm. This ensures a more energy efficient start for your vehicle and can increase your energy efficiency in the winter. For example, the NRC says that a block heater can improve the overall fuel economy of your vehicle by up to 10% when the temperatures reach -20°C. When they drop an additional 5°C, the NRC predicts that you can save as much as 25% for a single, short trip.

Do not leave your block heater running all night. Instead, purchase a block heater timer and set it for 2 to 4 hours (estimates vary) before you plan to leave in the morning.

Buying a Block Heater for Your Vehicle

First, check if your vehicle already has one installed. It’s possible that you simply just need the appropriate cable. If your engine does not have a block heater, ask your vehicle’s manufacturer which block heaters work for your vehicle. Block heaters do not come in one size that fits all. To install it, ask your mechanic.

You don’t need to plug-in your car every night during the winter. A block heater only helps in temperatures below-15°C. However, when you do need one, a block heater can help improve fuel efficiency, cut off a few minutes of idling time in the morning, and help maintain your engine block in good condition.