It depends on the quality of the insulation in the walls
You'd have better luck googling for "how to size an air conditioner".
There's also a limit to air conditioners, in that they can only draw so much current from a normal wall outlet. I used to have an air conditioner that drew the maximum 15 amp @ 120 Vac. It would cool most of the appartment I used to live in, but the wiring was faulty, and the starting current kept tripping it up.