its the same with any small capaicity engine, i've never once used my a/c because I it can struggle to get up hills in gears youd normally cruise up fine in a high gear. If I drive at 70 and switch it on the car drops to 60-65 instanty! I read its someting stupid like 25% more fuel used when its on as well. Big engined cars dont really have that problem, with all that torque swimming about you could turn over another engine without noticeing any change! The great thing is im in scotland, a/c is never needed! A good de-misting system is however. What a **** country!

 

i guess this is a bit off topic, but i used to turn my ac off and put it on high heat with out the fan running and race my friend for fun