AC and Gas Mileage

I have an 05 Accord

Is the amount of gas used by the AC proportional to the temperature
setting? I was thinking that the lower the temperature the more often
the compressor would have to come on. Is this accurate?

thanks,
-Mark

 

Of course. When the compressor runs, it takes some engine power.

But if the compressor is running 75 percent of the time, or 85
percent of the time is going to mean extremely little in terms of gas
mileage.

 

: I have an 05 Accord
:
: Is the amount of gas used by the AC proportional to the temperature
: setting? I was thinking that the lower the temperature the more often
: the compressor would have to come on. Is this accurate?
:
: thanks,
: -Mark

No. When you have the A/C on, the compressor is running pretty much all the
time. If you set the temperature higher than the minimum setting, there's a
heating coil in the system that brings the temperature back UP to the
setting you want.

Paul

 

Interesting points. Now, I'm not sure of something:

When you tip in on the accelerator, from a steady cruising speed, does
it curb or temporarily disengage the a/c compressor, as many cars have
been designed to do, for purposes of 'giving the power back' to the
engine?

 

I ran the A/C constantly in mixed city/highway (mostly highway) driving
and averaged 30MPG in my 95 Accord 4cyl/Vtec.

 

So whats the difference if your hot and want the comfort who cares how much
gas it uses.

Tom

 

The amount of additional gas used is proportional to the compressor
"on" time and the outside abient temperature.

Professor
www.telstar-electronics.com

 

"twfsa" wrote

In fact, I have yet to notice any difference in gas mileage between a/c on
or off in my '04 Accord 4-cyl auto.

 

As it would relate to compressor run time, yes.

The compressor run time is determined by the evaporator outlet
temperature. As long as the evaporator temperature is above 33F. the
compressor will run. Regardless of the setting.

Best fuel economy can be had by driving with ac off and windows
up. Any time the ac is on, it costs gas, and is proportional to
compressor on time. So the question is: how much do you like to sweat?

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This is what confuses me about the discussion of AC relating to fuel
economy. I have a 93 Honda Accord & I can feel when the compressor
clutch engages & disengages. When it engages I can feel the engine is
under more load(more vibration at stop or slight drop in acceleration or
speed in motion). Surely fuel economy increases when the compressor is
disengaged even with the AC "on".
Thanks for your input.
Rich

 

On the V8 engines a "properly operating" air conditioner will cause about
a 1 to 1½ mpg impact in fuel economy in around town driving, slightly less
with sustained driving at highway speeds. The operative phrase here being
"properly operating".