Except for the dehumidification advantages of a right sized AC unit, is there any operating cost advantages one way or another? In other words if the same house and air handler has a 2 1/2 ton condenser vs. a 3 or 3 1/2 ton condenser, will the electric costs be the same. The smaller unit will run longer to get the house to the desired temp but will draw less power. While the larger will get the temp there faster (although not pull as much moisture) but draw more power while it is running. This is also assuming all other factors equal including SEER, outdoor temperature, etc.