Major drop in gas mileage with A/C

TED AGOSTINO

MEMBER
2012 SUBARU FORESTER
4 CYL
4WD
AUTOMATIC
62,000 MILES

We recently moved from Maine to South Florida, so are doing much more city driving and using the air conditioning much more than before. Gas mileage has dropped from 26-27 mpg to 15-16 mpg, which seems extreme. I may simply be more aware of it, but it seems like the power drain when the compressor kicks on is greater, too: interior lights dim, and I can even feel a change in the brake pedal. A/C still cools quickly, and air is good and cold.
Car is well-maintained: all scheduled dealer maintenance, including the major 60,000 once-over just before we moved.
Is this drop in efficiency to be expected, or is there something wrong with my A/C compressor?

3 Replies

BMDOUBLE

MECHANIC
1,139 POSTS

This looks absolutely normal to me. I handle the driveability concerns at my dealership and have for the past 27 years and can say that I see these concerns a lot. It sounds like you are up to par on maintenance which is all that I usually recommend to folks with these concerns. Stop and go, higher ambient heat, air conditioner usage, and hilly terrain are the biggest effectors of fuel mileage. There is also a short period of time for the transmission to adapt to a different type of driving, along with a different barometric pressure associated with an altitude change (if any). Your air conditioner operation sounds normal as well. These are great cars!