Car A/C - how does it effect gas mileage?

yOyOYoo

Senior member
Mar 21, 2001
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As per the heading, does turning on AC in the car have any effects like decreasing gas mileage?

I would think that it doesn't make a huge difference or anything, but I have this friend who is an AC Nazi and NEVER turns on the AC, because he says it saves so much gas.

Anyone have an answer for me? thanks.
 

FoBoT

No Lifer
Apr 30, 2001
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yeah, but just a little bit, like maybe 5%

who cares? you want to cook in your car?

i have no A/C in my car and it has been ~90+ for weeks, i get cooked everyday
 

boyRacer

Lifer
Oct 1, 2001
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Originally posted by: FoBoT
yeah, but just a little bit, like maybe 5%

who cares? you want to cook in your car?

i have no A/C in my car and it has been ~90+ for weeks, i get cooked everyday

Same here... :(
 

ElFenix

Elite Member
Super Moderator
Mar 20, 2000
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it does, and the smaller the engine the bigger the hit
 

TheNinja

Lifer
Jan 22, 2003
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it is true that turning on your AC reduces your gas mileage a little. But what most "AC Nazis" who won't turn on the AC don't realize is that when you ride with all your windows wide open you screw up the aerodynamics of your vehicle and your open windows cause more drag, which also reduces your gas mileage. So unless you ride around with AC off and windows up and bake in your car, you could just as well run the AC and be comfortable.
 

rh71

No Lifer
Aug 28, 2001
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Originally posted by: Heisenberg
I swear there was a thread about this just a few days ago.
Yes, there was. And also a month ago... and probably many more times before that.

 

acemcmac

Lifer
Mar 31, 2003
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I've always been able to feel a noticable horsepower drop between ac and no ac, between every late model car I've ever driven with it...

volvo v70, subaru legacy, camry, corolla, mustang, dodge caravan... if it takes from horespower... i dunno... but its interesting....
 

JoPh

Diamond Member
Aug 8, 2002
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I tried it in my car as an experiment.

2003 Chevy Impala LS... v6 engine.

W/O AC and windows open I got about 31 MPG

W AC on and windows closed I got about 31 MPG



That settled it for me. I would rather have windows up and be comfy.

Note.. both were on almost entirely highway driving.
 

Goosemaster

Lifer
Apr 10, 2001
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Originally posted by: boyRacer
Originally posted by: FoBoT
yeah, but just a little bit, like maybe 5%

who cares? you want to cook in your car?

i have no A/C in my car and it has been ~90+ for weeks, i get cooked everyday

Same here... :(

Diito..


<----car is in the shop:|
 

pennylane

Diamond Member
Apr 28, 2002
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I heard for newer cars it's not as big a deal (from my friend). He drives an 86 porsche (think it's an 86). He tries to avoid AC on his car cuz he loses a lot of effiency when it's on.
 

Ferocious

Diamond Member
Feb 16, 2000
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I usually have the AC on and the windows cracked quite a bit.

Makes for cool winds.
 

erikiksaz

Diamond Member
Nov 3, 1999
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Originally posted by: TommyVercetti
Quick question, why are ricers always driving with the windows down and an arm out?

The windows might be down because they think they'll save gas (thinking back to AC). But, as for the arm, i don't know what you mean. I stick my arm+flathand out the window every once in a while--it's fun as a makeshift airplane wing.
 

CraigRT

Lifer
Jun 16, 2000
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the only reason it's more gas is cause your car loses power from the compressor sucking juice.
you put more into the car to make it move that's all... it doesn't really use gas, the compressor just needs to turn on and off to pump the freon..
 

Imdmn04

Platinum Member
Jan 28, 2002
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does turning the a/c up to the highest level have more of an impact than turning it to low?
 

rh71

No Lifer
Aug 28, 2001
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Originally posted by: Imdmn04
does turning the a/c up to the highest level have more of an impact than turning it to low?
While I notice HP drop while the A/C is on, I never notice the low-high setting of it affecting anything. So your answer is likely - no.
 

vegetation

Diamond Member
Feb 21, 2001
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Originally posted by: Imdmn04
does turning the a/c up to the highest level have more of an impact than turning it to low?

Yes, but the mere fact the compressor is engaged causes a lot of parasitic drag. Main reason why we need to up the car voltage and start using electric powered compressors.