Idling To Warm Your Car?

People across the US — and especially those whose cars have remote starters — often fire up their engines in the cold of winter long before they start driving. But it turns out that this is one of the biggest energy myths.

The Washington Post reports that a 2009 study found that on average, Americans thought they should idle for over 5 minutes before driving when temperatures were below 32 degrees.

Like many misconceptions, the idea behind winter car idling begins with a kernel of truth. Cars do get worse fuel economy when it’s really cold out — they are at least 12 percent less fuel efficient, according to Environmental Protection Agency and Energy Department. And it does take longer for the engine to warm up and reach an optimal driving temperature in cold weather.

Moreover, older cars — which relied on carburetors as a crucial engine component — did need to warm up to work well, according to several auto industry experts. Without warming up, the carburetor would not necessarily be able to get the right mix of air and fuel in the engine — and the car might stall out. During the 1980s and into the early 1990s, however, the auto industry did away with carburetors in favor of electronic fuel injection, which uses sensors to supply fuel to the engine and get the right air and fuel mix. This makes the problem of warming up the car before driving irrelevant, because the sensors monitor and adjust to temperature conditions.

Idling in winter thus has no benefit to your (presumably modern) car. Auto experts today say that you should warm up the car no more than 30 seconds before you start driving in winter. “The engine will warm up faster being driven,” the EPA and DOE explain. Indeed, it is better to turn your engine off and start it again than to leave it idling.

Eliminating the cold start idling not only saves in fuel consumption, but also reduces the carbon emissions and its affect on the environment. The study found that if people would just knock off unnecessary idling of this sort, then consumers as a whole would save $5.9 billion per year on fuel costs (based on the cost of fuel in 2008). The saved emissions, the study noted, would be “larger than the emissions from the soda ash, aluminum and limestone industries combined.”

Read the entire Washington Post article for more information or check what the EPA and DOE has to say about it.