Gas savings myth: Windows up vs. Windows down

By Scott Leamon
WSLS10 Reporter
Published: July 17, 2008

  Our story on looking for ways to save gas money where we tested the old theory on windows up versus windows down was tough to plan but fun to execute.

  If you didn’t see it, we found you save slightly more gas when you drive with the air conditioner on and the windows up, then the AC off and windows all the way down.

  We ran at a constant 40 mph at the Shelor Motor Mile Speedway in Radford, which was gracious enough to allow us to conduct the test.

  It ended up being a 1.8 mile savings with the windows up versus the windows down.

  We did a ton of more research though that never aired in the story.

  One thing we found out was there is a “magic number” as to mph when it saves you more to have the windows down.

  That “magic number” is around 30 mph, in mostly city stop and go traffic of course.

  We confirmed that number with AAA, and a pair of certified master mechanics we regularly consult for these types of news stories.

  Experts say you might save more gas money with the windows down and AC off driving at those low speeds.

  The reason is there will be less aerodynamic drag than when you run at higher speeds out on the highway.

  Air conditioners run much more efficiently than they used to, according to experts.

  But at lower speeds, most agree it saves money to roll the windows down and turn the AC off.