the amount of power your aircon will use entirely depends on which kind of AC it is.
generally most small engined/lower spec cars have variable venturi type which utilises a compressor with a clutched pulley that kicks in or out & & because when its "In" the compressor is working at full whack & you can feel that extra load on the engine!
the other kind is fixed orifice that generally is active all the time. the pump is constantly engaged but it has a variable swash plate inside so if you dont need a lot of pressure it doesn't push a lot of pressure so load on the engine is reduced a lot of the time
to put it in basic terms say we need 50% worth of cooling
the fisrt system will have its compressor kicking in & out but working at 100% when active for the approximately half the time
the climate control type system will just have the compressor working at 50% of its capacity for 100% of the time
the climate controlled car will be a lot smoother & the temperature should stay relatively constant
the std AC car will get warm then clonk the compressor will kick in, the fans will blow cold for a while cooling the car then the compressor will disengage & cabin temperatures will start creeping up again! and so it goes on.......................
personally mines never ever been turned off, its active all year round as AC also dehumidifies the air which demists you quicker & helps your windows stay clearer if you have a car full of damp people etc
heres something to consider!
any AC system is kept gas tight by rubber seals. these rubber seals are kept healthy & moist by oil in the refrigerant which coats them as the system is used. if you leave your AC switched off for long periods of time these seals can & do very often dry out & all the refrigerant gas escapes!
every year during the first hot week we are mobbed by customers complaining " my AC's not working, it worked fine when i used it last summer" etc
so in their quest to save money how does £100 to recharge the system sound or another way is in their quest to save a rainforest by not turning it on because of emissions has led to a leak of R134a refrigerant which is a known greenhouse gas with very severe penaltys for accidental discharge!
The 1997 Kyoto Protocol puts R-134a as one of the 6 greenhouse gases that must be handled with extreme care.
anyway the morale of the story is if you got it you may as well use it
