How efficient is an air conditioning unit?
Air conditioning units are typically able to produce 3 kilowatts of heat for every kilowatt of electricity that it uses.
A modern unit can have an energy rating of A+++ and being inverter driven means it will only work as hard as it needs to. It is cheaper to leave a unit running all day on a moderate temperature, but not as efficient being set to maximum settings forcing it to run flat out working harder than it really does need to do.