Warming up your car before driving is a leftover practice from a time when carbureted engines dominated the roads.  But it’s been about 30 years since carbureted engines were common in cars.

In addition, the term “warm-up theft” is a widely used term among car thieves to describe the stealing of a car that has been left running and unattended.

And then there’s the danger of CO concentrations when warming a car in a garage – either a closed garage or one that is open.  In an Iowa State study, warming up a vehicle for only 2 minutes with an overhead door open raised CO concentrations in the garage to 500 ppm.

So what should you do?  Start it up, make sure all your windows are clear of ice/snow/fog, and just drive the thing!