Is it more efficient to leave your car idling? #
May 27th, 2008 | In Worth Knowing
Short answer: no. Slightly longer answer:
Virtually no fuel is wasted during startup, and only a thimbleful is burned as the car roars to life. So forget about the 30-minute axiom you were raised on—the threshold at which it makes more sense to shut off rather than to idle should be expressed in seconds, not minutes.
A lot of environmental organizations advocate the 10-second rule: If you’re going to be stopped for more than 10 seconds, it’s best to shut off your engine.