05' Ford Focus ZX3 Hatchback Aeromods

[tru]

typically the AC will knock down my mpg's from upper 30s to 40 down to low 30's average. as far as comparison between on vs windows down, its close to the same if i cycle the AC at lights and keep it on recirc while cruising and bump the air on and off depending on how warm it gets in the car.

if im doing sustained driving above 45 i will just give up and turn the air on.