Does Air Conditioning Affect Fuel Economy?

As the temperatures rise into the summer months, A/C becomes a routine part of driving. Without it, the interior of your vehicle can reach near-unbearable temperatures on hot days. With many using their air conditioning daily during the summer, the question of its effect on MPG becomes a concern for some. 

In this article, we’ll cover how your A/C usage can impact fuel economy, why this occurs, and how you can help maximize your efficiency in the future. 

Head unit A/C control dials and screen

Does A/C Hurt Your MPG?

Yes, air conditioning does affect the fuel economy of your vehicle. Like the alternator and water pump, the A/C compressor in your vehicle is driven by the engine’s accessory belt. This reliance on the engine’s power output requires a little more fuel to keep everything operating.

But how much?

According to the U.S. Department of Energy, running your air conditioning can decrease fuel efficiency in conventional vehicles on very hot days by up to 25% on short drives. This number can be even higher for hybrid or plug-in hybrid vehicles. Of course, it won’t always be blazing hot outside and in most circumstances, your A/C won’t be as taxing on your fuel consumption. 

A/C vs. Windows Down

A common debate for drivers in hot areas is the effects of running your A/C versus rolling down the windows. While some believe the drag of having your windows down outweighs the increased strain put on your engine by A/C usage, others believe the opposite.

In a 2013 study, the Society of Automotive Engineers (SAE) conducted testing with a 2009 Toyota Corolla and a 2009 Ford Explorer. With the Corolla, the results suggested the vehicle had to travel over 80 MPH before the drag of rolled-down windows made it less efficient than driving with the A/C active. Using the Explorer, they found that having the windows down was more efficient at lower speeds with minimal difference at speeds above 60 MPH.

At the end of the day, which option provides the best efficiency may just come down to various factors such as the engine size, aerodynamics, and the speed at which you drive. 

Of course, you’ll get the optimal fuel economy with both the windows rolled up and the A/C off, but that’s far from ideal on a hot summer day. 

Motion-blurred guardrail and trees shot through an open window while driving

How to Maximize Fuel Economy

Even when it’s not practical to drive without your A/C running, there are still a few steps you can take to maximize your fuel economy and make up for some of the A/C’s negative effects. 

  • Brake & accelerate gradually
  • Ensure proper alignment and tire pressure
  • Use a sunshade to keep your car cool when parked, lessening your reliance on A/C
  • Use quality synthetic oil
  • Remove ski/bike racks, mounts, rooftop cargo boxes, and other accessories that could increase drag while driving

A/C Services in Peoria, IL

If you’re experiencing issues with your A/C system, the technicians at Beachlers Vehicle Care & Repair have the expertise and equipment to properly repair your climate control system and keep you cool this summer. Give us a call or schedule online today to secure an appointment with our friendly and knowledgeable team!