top of page
  • Writer's pictureJonnie Hendrickson

When Do I Plug In My Car? The Surprising Answer.

Updated: Jan 30

During the winter months, one of the most common questions we get is, “When should I plug my car in?"The answer may surprise you!

car plugged in during winter

Plug in When the Temperature Sinks Below -15 Celsius

While opinions differ slightly based on what you drive, the consensus is when temperatures sink below -15 Celsius, it's time to consider reaching for your extension cord.

While modern cars should start in -30C weather without being plugged in, they won't like it, and its certainly not the best when it comes to longevity.

Liz Kulyk, a communications manager from CAA Manitoba notes,

“It’s in your car’s best interest to plug it in before you use it, around -15C. It’s for the longevity of the car – to make sure the engine components are getting enough oil and to reduce wear.”

How Plugging in Heats up Your Car in Half the Time

What happens when you plug your car in, and why is it so important even in milder winter weather?

When you start your car, oil is pumped through the engine block to lubricate all the moving parts involved in operating your vehicle. At colder temperatures, oil thickens, becoming increasingly resistant to flow and creating more friction. Any increase in friction results in more wear and tear on engine parts.

Plugging your vehicle in activates the engine block heater. A block heater warms the engine coolant and engine block, which in turn warms your oil. Warmer oil “thins", causing it to flow faster and lubricate engine parts rapidly, reducing wear and tear on your car's engine and many of its crucial parts.

While a warm engine doesn't warm up the interior of your car (wouldn't that be great?!) it will give you a head start on the defrosting process, cutting the wait time for hot air in your A/C system from 10 minutes to about 5 – well worth it on a cold day. Plugging in your car is a more efficient way to heat up the interior than allowing your vehicle to idle for 20 minutes before driving.

Plugging in is More Efficient & Better for the Environment

Cold engines burn more gas and emit more exhaust, reducing your fuel efficiency and costing you extra at the pump. Plugging your vehicle in "preheats" your car, benefitting you and your wallet. It also has a tremendous environmental effect. CAA reports that preheated cars emit 15x fewer hydrocarbons, 6x less carbon monoxide, and 4x less nitrogen oxide at startup than vehicles that aren't using a block heater. Plugging in during cold weather is just one more small step each of us can take to help protect our environment.

Your Car Needs to be Plugged in for 3-4 Hours

Generic guidelines recommend plugging your vehicle in 2 hours before operating it, but in the extreme cold of our Winnipeg winter, CAA recommends connecting the cord 3 to 4 hours in advance of driving.

One other quick tip for you. While 2 hours may not be enough time for your engine block to work its magic, exceeding 4 hours appears to be equally ineffective. A 1972 Canadian study conducted at the University of Saskatchewan found that a block heater reaches maximum heat at around 4 hours, after which, any additional heat is swallowed up by the cold.

Plugging in your vehicle is a great way to preserve engine parts that are susceptible to friction, increase fuel efficiency, warm up your interior, protect the environment, and ensure that your car starts reliably on a cold day.


Plug in at temperatures of -15C and colder

Plug in 3-4 hours before driving to reach maximum engine block heat

Plug in, don't idle! The AC will heat up the interior in half the time!

Plug in and protect the environment by reducing the 3 most harmful emissions at startup by 15x, 6x and 4x.

Plug in safely by using a new extension cord, avoid pinching the cord with your hood, and keeping the connections dry and clean.

504 views0 comments

Recent Posts

See All


bottom of page