YTCEC Blog

To Idle or Not to Idle – There’s No Question About it

In this day of high fuel costs, a tight economy, population growth, and climate change, it is imperative that we are all armed with the current facts about engine idling.

Idling is defined as running a vehicle engine when the vehicle is standing still. It sounds downright silly, really. Who would want to do that? We don’t go to work each day so that we can pay for our car to get zero miles per gallon. And we all need clean air to breathe – why would we needlessly spew exhaust into it?

Well, the majority of us in Bozeman do idle needlessly, most commonly when we’re warming up the engine, “running inside for just a minute,” using the drive-thru, staying comfortable while waiting inside a vehicle when it’s cold or hot outside, picking someone up, dropping someone off, or talking on a cell phone. While there are times when we are legally obligated to idle our vehicles, such as at a stop light, the above reasons for idling are typically unnecessary.

Many of our beliefs about idling are out of date, from the 1970s and earlier, and don’t apply to newer vehicles. Following are two of the most common myths about idling:

Myth: On a cold day, it is best for the health of a vehicle to warm up the engine by idling until the engine is warm.

Truth: For temperatures above 32 degrees, there is no need to warm up most vehicles. From 0 to 32 degrees, you should warm up most vehicles for 30 seconds. For temperatures under zero, you should warm up the vehicle for 1-3 minutes. In all cases, it’s best to idle for the recommended time, then drive slowly for the first minute or two. (Excessive idling can actually damage engine components.)

Myth: It uses more fuel and costs more to restart an engine than it does to let it idle for a few minutes.

Truth: If you’re going to be stopped for more than 30 seconds (except in traffic) turn off the engine. (Actually, idling for more than 10 seconds uses more fuel than it takes to restart the engine, but in order to offset potential incremental maintenance costs, the breakeven time is 30 seconds.)

There are important reasons to change our idling behavior, perhaps the most compelling being our health. Idling releases hazardous chemicals into the air including carbon dioxide (CO2), carbon monoxide (CO), hydrocarbons, nitrogen oxide, and particulate matter. These idling byproducts are related to ill health effects ranging from asthma to cancer, and no one is immune when it is in the air that we breathe. Ironically, some of the most common idlers are parents running their engines and spewing these toxins outside of schools and activity venues while waiting for their children.

Environmental concerns are also paramount. Emissions from idling contribute to smog, haze, greenhouse gas emissions, and ground level ozone. Has anyone looked out the window towards the north from Bozeman on a clear day? You may have noticed that the air is not so clear.

Saving money and fuel is another reason to stop idling. The average annual fuel cost for a vehicle that idles ten minutes each day is 20 gallons/$75 for a small car, 40 gallons/$150 for an 8-cylinder engine, and 15 gallons/$67.50 for a diesel engine. Remember, these savings could be yours by doing nothing more than turning off your engine when it is unnecessarily running. A no brainer!

We’ve all become familiar with the slogan “Hang Up and Drive.” Now it’s time to consider another – “Idling Gets You Nowhere.”

Elin Hert lives in Bozeman and is a volunteer member of the City of Bozeman’s Idle Free Bozeman working group. 

This article was first published as a guest column in the Bozeman Daily Chronicle and can be found HERE.

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