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VERIFY: Running a car's AC does decrease fuel economy. Here's how to combat that

The Dept. of Energy says air conditioning is the main reason drivers see reduced fuel economy in hot weather, but there are ways to improve it.

CHARLOTTE, N.C. — While gas prices are starting to decline after reaching new records, the pain at the pump is still very real for many drivers.

AAA reports the national average for a gallon of regular gas was $4.93 Friday, which is down 5 cents from the beginning of the week. However, it's still $1.85 higher than the average two years ago.

Some drivers might be wondering how to stretch their buck, even if it means cutting the use of some extras in their car.


Does running your car's air conditioning (AC) in hot weather reduce its fuel economy?




This is true.

Yes, running the air conditioning can decrease a car’s fuel economy.


Air conditioning in a car runs off gas, according to the Department of Energy and EPA. In fact, the Department of Energy cites AC as the main reason drivers experience a decrease in their fuel economy during hot temperatures.

Running the air can reduce a car’s fuel economy by more than 25%, particularly on short trips, and drivers should expect an even bigger drop while idling.

"When you're idling, your vehicle's not moving," Fallone said. "So, you're essentially getting zero miles per gallon at that point."

But before cutting the cool breeze and opting for a windows-down drive on the interstate, drivers should consider that that will also reduce fuel economy.

It's because open windows add more aerodynamic drag, requiring more energy to keep a certain speed. The Department of Energy said the drag grows as speed rises.

How to improve fuel economy

The Department of Energy offers some tips to combat the cut in fuel economy:

  • Roll the windows down at lower speeds; use the AC at highway speeds.
  • Don't use the AC more than needed or set the temperature lower than needed.
  • Park in the shade or use a sunshade.
  • Drive with the windows open for a short time before using the AC. Letting hot air out of the cabin first lessens the demand on the AC.
  • Don't idle with the AC running before driving. Most AC systems cool the vehicle faster while driving.
  • Plug-in hybrid and electric-vehicle drivers can pre-cool the cabin while their car is plugged into the charger. They can also use a warmer temperature setting to lessen the drain on battery.

VERIFY is dedicated to helping the public distinguish between true and false information. The VERIFY team, with help from questions submitted by the audience, tracks the spread of stories or claims that need clarification or correction. Have something you want VERIFIED? Text us at 704-329-3600 or visit /verify.

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