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View Full Version : Gas mileage and A/C


Chaad32
07-22-2006, 11:51 AM
I was wondering if having your A/C on low actually helps save gas versus having it on hi. I'm no engineer, but doesn't the loss of gas mileage come from the extra strain it takes to drive the A/C pully, and if the A/C is on (no matter how hi or low) the pully is being spun, so doesn't this mean that it doesn't matter?

ECHOKnight2000
07-22-2006, 02:48 PM
I was wondering if having your A/C on low actually helps save gas versus having it on hi. I'm no engineer, but doesn't the loss of gas mileage come from the extra strain it takes to drive the A/C pully, and if the A/C is on (no matter how hi or low) the pully is being spun, so doesn't this mean that it doesn't matter?


You are right to a certain extent, the A/C on eats at gas, period...but if you have it full blast it will eat more at your gas, so you are right at that, if you had it on low it won't eat as much...or what you could do is have it on for awhile till your cool enough and then turn it off until you need it but that might be a nusince. Or you can have the dial at the cool setting and have the air circulation come from the outside with out having the A/C on, of course you are at the mercy of the weather, cause obviously the air coming in is from the outside but I do it often and it can get decently cool even on warmer days, it depends on what your threshold is as far as cool or heat.

boxerboy
07-22-2006, 03:57 PM
Is the ac on or off? Is the temp control just a mixing valve? I have been running my ac since I got my car, (when I am driving) its been a month friday. I leave it on the coldest setting and run the fan on 2 once it cools the inside.

Pompeii66
07-22-2006, 04:08 PM
Had my liftback for 2 weeks now.
Been hot and running the air ever since I took delivery.
Filled up thre times now and have been averaging 32 MPG.
Hoping the mileage increases when it gets cooler and the air is off.
I really would like to see around the 39MPG listed.

Chaad32
07-22-2006, 05:20 PM
OK....so does the tepm setting havbe anything to do with gas consumption?

twixt
07-22-2006, 05:55 PM
no, as longas the ac is on it is flowing the coolant at the same rate, the temp setting just mixes warm air into the cooler air. also, the low high setting has nothing to do with milage, it just makes the fan push the cold air faster. the pump is going at the same speed no matter what you do

Chaad32
07-22-2006, 06:04 PM
That is good to know. My girlfriend always makes me keep the A/C on low because she doesn't want to burn up gas. HAHA I win.....:evil:

Chaad32
07-22-2006, 06:06 PM
Although, doesn't the A/C pump turn on and off periodically depending on how hi the fan is going? Or is what you are saying is that no mater how hard the fan is blowing the A/C is always kept at the same temp in the coils and thus the same gas is being used.

ECHOKnight2000
07-22-2006, 07:06 PM
no, as longas the ac is on it is flowing the coolant at the same rate, the temp setting just mixes warm air into the cooler air. also, the low high setting has nothing to do with milage, it just makes the fan push the cold air faster. the pump is going at the same speed no matter what you do


Opps! My bad:rolleyes: :biggrin:

Like Chaad32 mentioned when I don't have my music up loud:biggrin: I can hear the A/C pump go off and on, I can hear a different tone in the sound, like its working then it shuts off I don't have my a/c on, its just the cool setting with the circulation coming from outside, unless I'm hearing something else...I'm not stating a problem just an observation.

Chris07LB
07-22-2006, 07:21 PM
I keep it as high as I need it to be comfortable. I wont pinch penny's to make my commute any less uncomfortable then it has too.

Dylanby
07-22-2006, 07:36 PM
I keep it as high as I need it to be comfortable. I wont pinch penny's to make my commute any less uncomfortable then it has too.

Ditto.

Chaad32
07-22-2006, 09:24 PM
I have actually noticed in other cars that I have owned that when on the interstate and with the A/C on and the windows rolled up I get better gas mileage that with the windows down......

boxerboy
07-22-2006, 09:40 PM
more aero dynamic with windows up

Chaad32
07-22-2006, 09:44 PM
That is what I thought to....but I didn't realize how much aerodynamics plaied into the equasion.

LittleRed
01-28-2009, 03:30 PM
You can save gas by..cooling the car...turning off the a/c and putting it on recirc..thus recirculating the already cool air on low 1 or 2 setting it will stay cooler longer..i assume..until it gets warmer...then turn it back on...but may be wrong...makes no since to turn the a/c off and use the fresh air setting , thus bringing the warmer air in...using the a/c at highway speeds..has a pretty minute effect on milage..since the car gets close to 40 mpg...why not be comfortable...thats why they invented a/c..people are too obsessed with gas mileage..cant we just enjoy the car..i do....it already saves gas by not having a power steering pump...

NJBob
01-28-2009, 05:26 PM
You only lose 2-3 mpg by using the air. At speed you still lose with the windows open. May as well use the A/C. Remember if your car has been sitting all day in the heat, all those surfaces (upholstery, dash, steering wheel) are kicking out heat big-time so it'll take longer to cool down.

Bob_VT
01-28-2009, 05:39 PM
:laugh::laugh::laugh:Sharp as tacks guys...... answering a post from JULY 2006 !!!! :clap::clap::clap:

voodoo22
01-29-2009, 08:13 AM
:laugh::laugh::laugh:Sharp as tacks guys...... answering a post from JULY 2006 !!!! :clap::clap::clap:

It took them 3 years to come up with the wrong answers:biggrin:

NJBob
01-29-2009, 05:31 PM
Some people, like me, won't go back 3 years hunting for a post. A lot of noobs just want answers and ain't that why we're all here....to help each other? Right on!!