I Bought Into a Myth about Car Idling

[image found on Carbon Offset Solutions]

Don’t ask me where I heard this, but for my entire life I believed that starting a car used up the same amount of fuel as an idling car used in five minutes. So for as long as I’ve been driving (which is inching up on two decades now), I thought the “smart” thing was to leave the car idling for a few minutes rather than turning it off. Turns out I was completely and totally wrong according to this article. Idling for 10 seconds uses the same amount of fuel as starting a car in the first place. Idling a car for 10 minutes can use as much fuel as it takes to travel 5 miles. And even on the coldest days, idling your car for 30 seconds is all you need before driving away – the car will warm up faster on the move rather than idling (though the article says not to accelerate hard or drive at high speeds for the first 3-5 miles…which isn’t exactly practical advice in all situations).

I’m generally one of those types of people that thinks he’s right most of the time, but I try to keep myself open to correction and further learning…and I’ve just been schooled on the issue of idling.

  • Yeah, it is true. Thanks to ECU (Electronic Control Units) car engines of today are using less fuel at startup than the carburetor versions did. In fact, when I drove to get my drivers license, the drivers ed school (what’s the correct term again?) tried to learn us economic driving which means learning how to drive as efficiently as possible measured in gas consumption per distance. One tip was to approach the red traffic lights as slowly as possible, through down-shifting, as to not let the engine idle too much because of the thing you just mentioned. But sadly that doesn’t help me as much when I’m driving an Canadian assembled American car with auto transmission… 😉