My first question how much on average does using the A/C all the time affect gas mileage?

My second question is does turning the A/C all the way up force the A/C compressor to run all the time or is it running all the time anyway? By turning it down (fan or temp) does this make the compressor engage less. This may be a moot point though because I need full A/C on a hot day, I could turn it down on a cool night though.

 

Yeah i'd love to know that info to!

 

The compressor cycles on and off when the AC is on. This keep the evaporator from freezing up. A higher fan setting will make the compressor cycles longer to keep up with the higher airflow.
The compressor is very efficient and does not consume much engine power.
Having the window open causes more HP loss from drag than running the AC compressor

 

mythbusters (best show ever!) did a test on this, the conslusion: On their test cars, ford explorers, below 50 mph, its more efficient to keep the windows open, above 50 windows up, AC on. That doesnt mean it speaks for all vehicle because some compressors are more efficient than others, but its a good general rule.

 

I'm in Florida- we use AC even in winter!
I have made some trips without AC and the difference in mpg was negligable, maybe 1 mpg.

Walt

 

I have noticed a big differance in MPG between the 2. If I keep the AC off I can get 32 MPG, with it on for long times it will go down to 25-26. Now the big problem will be the drop due to winter temps, takes longer for engine to warm up.

 

Mythbusters TV show did research on windows open vs AC. They found below 45 MPH window open provides better gas mileage. Above 50 AC provides better mileage.

 

hey kanotoa i know you from mma.tv hahaha
glad you found this site as well

 

What's your handle there? Not enough room on MMA.TV to get all my trolling in.

 

The compressor in the xB is not a cycling compressor, but a variable displacement compressor. Rather than having a clutch that engages and disengages it is electronicly controlled to change it's displacement.

Check the service manuals...

Last long trip with A/C on all the way both direction got 36MPG on a 300 mile trip.

 

That was the first thing i noticed. Keep the windows up and the air on, and the M.P.G. stayed @ 33 to 34 , open the windows and it droped down to 30 to 31.

 

Thanxs

 

I don't notice hardly any difference on or off.

 

yep the mythbuster's inf was dead on..I proved it to myself all summer

 

when using the a/c do a couple things to save gas, let the engine get to temp before turning a/c on, drive with the windows down to get as much hot air out of the car before turning on the a/c, and i don't turn the a/c on until i get to highway speeds, so i don't accel from a stop with the a/c on, i get on average 35 mpg in my auto xB. the key to getting better mileage, with a/c or without, is not having a heavy foot and keeping the rpm's around or below 3,000

 

wow! i'll never tunr the ac off ever again!

 

Windows up or down, our Xb's have serious wind drag issues. lol

 

Ah.. good point...

 

I keep the AC on all the time for dehumidification purposes and cooling when hot out. Can't say I notice much difference when I switch it off - maybe a slight increase in power.

 

I'd still like to know how anyone can get 34+ mpg in this box. I've never got better than 32.