The ability of an AC to effectively cool a room is quantified with its British Thermal Unit (BTU). Yes, a higher BTU is better in most cases but not always. This is because a higher BTU can drive up your electricity bills. Consumers who don't require an extreme amount of power won't find the expenditure worth it. For instance, if you desire to cool just one small room, then an AC with an excessively high BTU output will cost far more in the long run.