AC & Fuel Savings

Q: With gas prices so high, I have been told to drive with my air conditioner off to save fuel.  I don't know if I can stand the heat.  Is this really going to save fuel??

A: Driving with your windows down and the air conditioning off consumes less gas than having the windows up and the air conditioner running.  This is absolutely true - that is, when you're cruising around town.

When you are driving across town, in stop-and-go traffic, it's more fuel efficient to drive with the air conditioning off, windows down.  When you have the air conditioning on, it reduces your car's fuel efficiency by up to 10 percent.  To achieve maximum fuel efficiency, motorists should avoid using the air conditioner at speeds below 40 mph and travel with their windows down.

But as your speed increases to 45 mph or highway speeds, wind drag becomes an issue.  Driving with the windows down increases the drag on your vehicle, resulting in decreased fuel economy by up to 10 percent.  Drive at speeds over 55 mph with the windows down, and you'll decrease fuel economy by up to 20 percent or greater.

Different cars react differently, and so the point at which you should roll up the windows and kick on the air will be different for each car.  Now you have to decide if you are willing to sacrifice a little comfort for fuel economy.

Here are a few tips to cool down your car faster:

  • Park in the garage or shade and use a windshield shade.  Your car will be cooler when you first get in.
  • Open your windows and vents to blow the hot air out faster before turning your air conditioner on full blast.
  • Fan speed does not affect fuel economy.  Turn the fan on the highest setting to cool the vehicle down faster.  Then, adjust for comfort.
  • Select your vehicle's recycle-inside-air feature.  It re-circulates the cooler inside air, rather than pulling in the hot outside air.