These days, the morning temperatures in my area are gradually dropping like tree leaves. And thus begins a tradition for many: warming our cars before we depart each morning.
The trouble with this habit is that it wastes gas — a parked, running car gets zero mpg. You might as well burn your money. Plus, warming up is totally unnecessary — modern engines don't need to be warmed up before you start driving, unless the outside temperature is below freezing. The best way to warm up an engine is to drive it, gradually increasing in speed; no jack-rabbit starts. Even if it's below freezing outside, an engine really only needs 30 seconds to a minute of warm-up.
Nevertheless, the myth that it's best to warm up your car before leaving is widespread. One of my neighbors does this religiously — nearly every morning this time of year, I see his car running, parked in his driveway. Whether I'm running behind and leave at 7:25, or I'm on time and depart at 7:15, his Honda Civic is warming up, burning gas and pushing out carbon dioxide. Rather than just scrape off the bit of frost on his windows, he leaves his car running, with the defroster running full blast. It's too bad, because odds are that Civic isn't getting nearly as good of gas mileage as it could. (Oddly enough, I drive the same car, maybe even the same model year.)
So, spread the word — there's no need to warm your car every morning. Doing so wastes gas and money, and spews more global warming emissions into the atmosphere. I'll see you outside in the morning, scraping the frost off our windows, without our cars running.
For more info, read Should I Let my Car Warm up Each Morning?
John Rockhold is a green car enthusiast and Contributing Editor for MOTHER EARTH NEWS. Find him on Google+.