A few weeks ago, I briefly touched on the subject of an idle vehicle in my post about lower fuel economy in winter. I'm back to expand on that after seeing vehicles this weekend sitting outside my neighborhood, idling to warm up as I stepped out.


It was a cold weekend here with occasional snow- weather that is certainly not limited to just the Midwest! Much of the country is seeing colder than average temperatures. It was frustrating for me to see at least three cars in just my neighborhood warm up for more than ten minutes each, just to provide warmth instead of being cold for a few moments while the car heated up normally. (READ MORE!)

Obviously at idle, a car nets zero miles per gallon, wasting away gasoline, and virtually increasing demand for gasoline (think if everyone idled five minutes per day, it would really add up!)

I have some statistics and facts on letting your car idle to clear up and inform you or why the practice should be eliminated. Fact: for every two minutes of idling, you use the same amount of fuel to drive 5,280 feet, or one mile. If you let the car warm up for ten minutes, you could have driven 5 miles on the same amount of gasoline. Letting your car warm up ten minutes then driving five miles effectively DOUBLES the amount of gasoline you use!

Winter results in more people idling their cars to warm them, but even in Winter you don't need to let your car sit and idle for five minutes to warm up when 15-30 seconds will suffice.

Did you know that ten seconds of idling can use more fuel than turning off the engine and restarting it? Fact.

Here are some more myths about idling your car (Source: Consumer Energy Center)
Myth #1: The engine should be warmed up before driving. Reality: Idling is not an effective way to warm up your vehicle, even in cold weather. The best way to do this is to drive the vehicle. With today's modern engines, you need no more than 30 seconds of idling on winter days before driving away.

Myth #2: Idling is good for your engine. Reality: Excessive idling can actually damage your engine components, including cylinders, spark plugs, and exhaust systems. Fuel is only partially combusted when idling because an engine does not operate at its peak temperature. This leads to the build up of fuel residues on cylinder walls that can damage engine components and increase fuel consumption.

Myth #3: Shutting off and restarting your vehicle is hard on the engine and uses more gas than if you leave it running. Reality: Frequent restarting has little impact on engine components like the battery and the starter motor. Component wear caused by restarting the engine is estimated to add $10 per year to the cost of driving, money that will likely be recovered several times over in fuel savings from reduced idling. The bottom line is that more than ten seconds of idling uses more fuel than restarting the engine.

Bottom line- don't idle your car to warm it up! Just wear a coat and let the car warm up on your way to your destination. Letting a car idle is a waste of fuel and costs everyone money at the pump! If we all shaved idling out we'd likely save millions of gallons of gasoline each year, lowering demand.