Myth Busting – Winter Vehicle Idling

Read time: 5 mins

Cold temperatures have been experienced across the country and it is safe to say that winter is in full swing. For those of you who drive in the winter, now is the dreaded time of year where you have to battle the cold to scrape off your windshield or possibly shovel your vehicle out of a snowdrift. Another thought that may cross your mind is making sure you have a remote car start, or making a plan to run out in the cold 20 minutes before you leave to let your car warm up. Although vehicle idling is a common practice in the winter months, it is actually unnecessary and results in increased fuel consumption and GHG emissions. It is time to bust the myth of winter vehicle idling.

Environment Canada conducted an experiment to understand the effects of vehicle warm-up in cold weather.i Vehicles were cooled to -18°C and were warmed-up for five minutes and then ten minutes before driving through a simulated cycle. After a five minute warm-up, fuel consumption increased by 7-14 percent and after ten minutes, fuel consumption increased by 12-19 percent. Carbon dioxide emissions increased similarly for the respective warm-up times as well. As such, the more time spent warming up your vehicle in colder temperatures, there will be increased fuel consumption and increased greenhouse gas emissions. Realistically, most modern vehicles are able to be driven after only a few minutes of being warmed up. With the Environment Canada test it was also noted that vehicle idling warms only the engine. It does not warm other parts of the vehicle, such as the wheel bearings, steering, suspension, transmission and tires. The best way to warm up the rest of your vehicle is by driving it.

Natural Resources Canada has published emissions impacts as related to vehicle idling.ii It is estimated that if Canadian drivers avoided idling for three minutes every day, carbon dioxide emissions could be reduced by 1.4 million tonnes annually. This would be saving approximately 630 million litres of fuel and the same as removing over 300,000 cars off the road for a year. NRCAN recommends that if you are idling for any more than 60 seconds, the amount of fuel consumption and emissions would be greater left idling than by turning off and restarting your vehicle. As such, unless you are sitting in traffic, it is recommended to turn off your vehicle if you plan to let it sit for longer than one minute. Around the world, the guidelines for turning off your vehicle if left idling are as follows: “in Europe, the recommended guidelines for turning engines off are 10 seconds in Italy and France, 20 seconds in Austria, 40 seconds in Germany and 60 seconds in the Netherlands. In the United States, the Environmental Protection Agency's Smartway and Drive Wise programs both recommend turning the engine off if you're stopped for more than 30 seconds.”iii

With data from NRCAN and Green Action Centre, we can calculate the individual CO2 emissions for idling for 5 minutes and 10 minutes and compare that to not idling your vehicle. According to NRCAN, burning 1 litre of gasoline produces 2.3kg of CO2.iv Green Action Plan estimates that, depending on your vehicle, up to ½ a litre of fuel can be consumed if idling for 10 minutes, or ¼ of a litre for 5 minutes.v Thus, idling for 10 minutes will produce 1.15kg of CO2 and idling for 5 minutes will produce 0.575kg of CO2. If we assume that a driver in January drives to work 5 days a week and chooses to warm-up/idle their vehicle each of those days during the month (20 days), 10 minutes of idling will produce 23kg of CO2 and 5 minutes of idling will produce 11.5kg of CO2 - all in one month! By reducing the amount of time you idle your vehicle in the winter months, you will be able to reduce the amount of CO2 entering the atmosphere from unnecessary fuel consumption.

Contrary to the above evidence against vehicle idling in the winter, many people believe that they should idle their vehicles for safety reasons and because engine oil has to be heated up before In this case, drivers should ensure they have the proper oil in their vehicles for driving in the winter. Today, multigrade oils are able to work at very cold and warm temperatures.vii Depending on many aspects of your vehicle, such as age and type, it is important to refer to the vehicle manual before winter hits and to ensure your vehicle is cold-weather ready.

It is safe to say that idling your vehicle for extended periods of time is not a necessary practice. It is important to note, however, that your vehicle should be clear of snow and ice before driving – drive safe this winter, everyone!


(Photo credit:

i “Vehicle warm-up”, Natural Resources Canada, accessed January 18th, 2016,

ii “Emission impacts resulting from vehicle idling”, Natural Resources Canada, accessed January 18th, 2016,

iii Ibid.

iv “Idling – Frequently Asked Questions”, Natural Resources Canada, accessed February 2nd, 2016,

v “Myth Busted – Idling Wastes Fuel”, Green Action Plan, accessed February 2nd, 2016,

vi “This is why people still think they should idle their cars in winter”, The Washington Post, accessed January 17th, 2016,

vii Ibid.


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