Skip the auto shop - Our mechanics make house calls

Q: How Much Does Using the AC Affect Fuel Economy

asked by on

How much does using the AC affect fuel economy?

A: There are several variables that will influ...

There are several variables that will influence the answer to that. It depends on your vehicle, how you drive, where you drive, and how hot it is outside. But there are some things that are certain: operating an A/C system does require extra energy.

Simply turning the A/C compressor on requires several horsepower from your engine that would otherwise be used to move your car down the road. There goes some gas money. A bit more electricity is required when operating the A/C and blower fan, so the alternator has to work harder. There goes some more gas money.

A frequently overlooked factor is the fact that driving with A/C turned off usually means the windows are open, making the vehicle less aerodynamic. A vehicle with the A/C on and the windows closed is more aerodynamic, thus consuming less fuel pushing through the air.

I suggest you do a test to find out what the impact of A/C operation is on your own vehicle’s fuel economy in hot weather. Monitor your gas mileage over a typical warm week without using the A/C. Then check your mileage for a warm week while using the A/C whenever you drive. You will likely see a small difference. If you are even able to complete the test, that is! Trying to drive without A/C in hot weather may convince you that it is so worth it that you will no longer care about the 1.5mpg penalty.

Should you run into any problems with your A/C, feel free to reach out to a certified mechanic that can diagnose and make any repairs necessary to fix your air conditioner.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: When SUV is off, in gear & exited, it starts rolling

Hi there. If it is still on gear then it is going to roll. The only gear that you can put the vehicle in and it will not roll would be in park. This is the only gear that locks...

Q: Rattling and screeching noise

Hello. The A/C compressor clutch and pulley should be checked and you should replace the pulley only if the compressor is not leaking. If it is, then replace the complete compressor assembly. If you would like to have this checked,...

Q: My digital fuel mileage read out and is going up and down erratically

Most "fuel economy estimators" utilize the length of time the fuel injectors are open (we're talking milliseconds here) during each revolution of the engine while driving. As a result, small periods of acceleration or other load factors will have temporary...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.