Are there air conditioners with small backs?

Question:With bars on the windows, regular air conditioners do not fit.

Answers:
The "backs" as you put them are the condenser section. Haier does make some but you may want to look into a ductless split system. It has and evaporator (part that blows cold air) that hangs on the wall and a condenser that sits on the ground outside, connected by refrigerant lines. If you own the place, it would be a good investment, if you rent, try Haier for something that would fit within the bars.