How much does running your car A/C effect gas milage?

Answer 1

Depends. Running the A/C affects smaller engines more than it does larger ones, so it'll tax a 4-cylinder a heck of a lot more than it will a V-8. Also, running the A/C on the highway doesn't drag your gas mileage down as much as it does in the city. To give you an idea, running the A/C on a V-8 at highway speed is close to negligible, but running the A/C on a small 4-cylinder in the city can cut your gas mileage down by 3 or 4 miles to the gallon.

Answer 2

My understanding is the older piston type compressors took 15 horse power to operate. I would think the newer compressors take less. One way to find out is to drive conservatively through a tank of gas with the A/C off and make note of the mileage, then do the same with the A/C on and you should see a difference. Subtract the one from the other and that should give you an idea of the draw on the engine. I would figure they still take at least 10 H.P. to operate. Bottom line is they do have an effect on your mileage but each car and driver will get different results.

Answer 3

Not too much. I don't know the numbers, but it's maybe 10% at the most. I've also heard that it's more efficient to keep the windows down (as opposed to the A/C on) for speeds less than 40 mph, but more efficient to have the A/C on for speeds greater than 40 mph.

Some other factors that minorly affect gas mileage are having the correct air pressure in your tires and having your air filter replaced at least once a year. Check out this link: http://www.schleeter.com/reduce-fuel-consumption.htm

Answer 4

Depends on the speed at which you are travelling and whether the alternative is putting your windows down. If you are travelling over 40 miles per hour with your windows down, the loss in aerodynamics of your car - more drag means more power necessary to keep your car moving and thus wasted gas - more than offsets running the A/C.

The best way to save gas (aside from taking public transportation or biking): get the lead out of your foot.

Answer 5

The tv show Mythbusters did this problem (sort of). They found that below 50mph it was better for gas mileage to have your car windows open and not run the AC. Above 50, the wind resistance got so bad that it was better to run the AC with the windows shut. At the risk of making an atrocious pun ... pretty cool!

Answer 6

From what I understand it is less than running your car with the windows down. Something about the wind blowing in through the windows causing your car to slow down. You have to press the gas more to compensate. Makes sense.

Answer 7

I agree with Paul R. I watched that segment as well. Gas mileage will ALWAYS be affected with your driving habits, location of where you live. ieflatlands, rolling hills, mountains. Gas mileage will also be affected by the amount of cargo, or weight in the vehicle, tire inflation, the list goes on.

Answer 8

Depends because driving with your windows open can affect your gas mileage more. Usually if you are cruising for long distances the effect is negligible, but can affect it drastically on smaller trips.

Answer 9

Anywhere from 1-14%

Answer 10

It can absorb up to 10% of the power output of your engine>Regards Mike