How much gas does running your A/C (in your car) burn??

[gar598]

Sometimes, I sit in my car and listen to the radio with the A/C going. Is this burning a lot of gas???? It seems to me that it burns a considerable amount (from looking at the gas guage).

Any ideas??

 

[Pacfanweb]

The A/C running at idle would raise gas consumption by a negligible amount.

 

[kag]

one milliliter?

 

[mithrandir2001]

It's certainly not good for the car to idle, play the radio and blow the A/C. Strains the electrical system and it isn't good for the engine.

 

[Pacfanweb]

<<one millimeter? >>

Even less than that

 

[Viperoni]

at idle maybe you turn 10-15% more.........at speed it's a bit more due to the engine revving higher (worst part is you lose power!!!!!!!!)

 

[Spoooon]

How much of an effect do the fans have? A neglible amount? When I'm on the highway, I always have the fans turned way up when the AC is on. I figure the compressor is stealing most of the gas, so why not take full advantage. Is that the way to go?

 

[Aihyah]

yea i've heard it doesn't matter if you have your fan set at min or max with ac i leave it near min unless its really hot, i don't like the noise

 

[Engineer]

A study was done a few years ago...(sorry, don't remember where)....

said basically that at highway speeds, the drag from your windows being down was almost, and at times more, equal to the amount of lost power to the AC compressor.

Also, the engine doesn't rev higher....the onboard computer on cars now compensate for the onboard AC by increasing fuel or changing the mixture via the fuel injectors and/or timing.

I'm not an expert in this field, but I do happen to work for a company that makes AC components for the world major auto manufacturers.

 

[kag]

yeah you can loose up to 5-10HP when you turn it on, that is suck

 

[juiio]

With newer cars, the amount is negligible. With older cars, its definitely noticable, although I don't have any numbers.

 

[mithrandir2001]

Driving down the highway with the windows rolled down is one of life's simple pleasures, fuel consumption be damned.

 

[mastertech01]

Its variable with all kinds of factors, such as the compressor design, how much load it places on an engine will vary with the size and power of the engine. It can be a sizable differnce with a low powered 4 cyl engine and almost negligle with a large powerful engine, like a diesel truck engine. However the large engine usually also comes with a large vehicle and fuel economy is low with those vehicles anyway. It also depends on the outside temperatures and how long the compressor stays engaged. In extremely hot climates like the desert SW it can stay engaged almost continously during the summer in traffic conditions. As stated highway economy will be greater as cycle on times are shorter due to engine RPM and air flow across the condenser. Modern AC systems use lighter weight AC systems which help contribute to the greater econmomy, as well as swashplate designs as opposed to older piston designs. Freon types can affect efficiency as well. Altitude affects efficiency. Humidity affects efficiency. Running on Max Ac allows maximum efficiency as it allows interior air to be recirculated rather than cooling hotter outside air. With so many designs of AC systems, so many different vehicle applications, so many different driving conditions and terrain, weather conditions as well, the amount of efficiency is widely variable.

 

[gar598]

<<Driving down the highway with the windows rolled down is one of life's simple pleasures>>

umm not when your in NC in August and the traffic is moving @ 5 mph

 

[LAUST]

It also depends on the motor, in a car with a little 4 banger in it that's going to be much more of a load on the crank then on a truck like mine, also on most new cars not only do you enguage the compressor but it also turns the Radiator fan on also, so on vehicles with a belt driven fan it's real harsh, but ones with electric it's not much as far as the fan goes.

 

[Cyberian]

<< It's certainly not good for the car to idle, play the radio and blow the A/C. Strains the electrical system and it isn't good for the engine. >>


I do that sometimes, too.
What damage would be caused to the electrical system and/or engine?

 

[blueghost75]

What damage would be caused to the electrical system and/or engine?

That will cause no damage to your car. none more than driving it normally.

if you have a really old crappy car, then you could have problems overheating if the weather is hot. also, there have been cases of carbon monoxide poisoning from a car sitting in place idling (keep in mind, the people basically slept in the car while it was idling, it was still running when someone found the car a couple of days later)

 

[Midnight Rambler]

<< said basically that at highway speeds, the drag from your windows being down was almost, and at times more, equal to the amount of lost power to the AC compressor. >>

I can vouch for this.


<< Modern AC systems use lighter weight AC systems which help contribute to the greater econmomy, as well as swashplate designs as opposed to older piston designs. >>

But their refrigerant sucks, several degrees less capable in temp drop, so it all evens out somewhat.

 

[KEV1N]

And the AC system of every Camry I've been in smells like feet!

 

[dawks]

Adding to Engineers post, there was a study I read, maybe even the same one, the trade off speed is about 52km/h (I think it was kilometers, seems reasonable anyway) where its more effecient to use your cars A/C then drive with the windows down. Over that speed, the drag causes to much fuel consumption.

 

[Sluggo]

Good Read on the effects of aerodynamics and horsepower of automobiles.

 

[Pacfanweb]

<<<< It's certainly not good for the car to idle, play the radio and blow the A/C. Strains the electrical system and it isn't good for the engine. >>


Not. You can let the car idle all year, never cut it off, just drive to the store to fill the tank occasionally, and it won't hurt a thing.