Does Using Your AC Really Decrease Your MPG?

June 15th, 2015 by

SummerWe receive all kinds of questions from our drivers here at Bosak Honda Highland. Since many of the answers we give would be helpful to nearly any driver, we do our best to answer them here on our blog so that you don’t have to wonder anymore. With summer on the way, we wanted to address one of the most common questions our driver ask: does using your AC really decrease your mpg?

The short answer is yes, but is it worth it for you to drop your fuel economy?

Is Using the Air Conditioning Worth It?

Using your air conditioning takes quite a bit of power, and your engine only has so much to go around. If you want the same level of performance you would have without the air conditioning on, your engine’s going to need more gas. But if you have to choose between melting in the summer heat or spending a bit more on gas, we think it’s an easy choice.

Of course, you don’t have to choose between melting or using the AC when you can roll down the windows, and that’s where things get interesting. Driving with the windows down creates drag, making your car less fuel efficient, but the effects of drag are low at low speeds. This means there’s a sweet spot where the drag caused by having your windows down affects your fuel economy just as much as having your air conditioning on.

It is going to vary from car to car, but in general it’s advised that you keep the windows down when driving under 50 mph and switch over to the AC when you hit highway speeds. If you are really worrying about conserving fuel, though, you can always just keep your windows up and the air off, but we wouldn’t recommend it.

Schedule Your Air Conditioning Tune-Up

If your air conditioning doesn’t work or isn’t working as well as it used to, you should schedule a service appointment at Bosak Honda Highland and let our technicians recharge or fix up your air conditioning system. And don’t worry, running your air conditioning should not affect your fuel economy more than a few mpg at the most; it’s a small price to pay for a cool car in the summer.

Posted in Car Care