We ended up purchasing a house with a 4 ton 14 seer R-22 heat pump and a 3.5 ton evaporator coil in the air handler. I was told that the fan in the air handler is large enough for a 4 ton system. The compressor was not working when we moved in and was replaced under warranty. After the compressor was replaced the evaporator froze up. The HVAC people came out and changed the freon levels. Then the compressor kept blowing the circuit breaker. They HVAC changed the freon level again and the eliminated the problem. AT this time they discovered that we had a 3.5 ton air handler and a 4 ton compressor. The came to replace the 3.4 ton evaporator with a 4 ton evaporator. The factory rep. sent a 4 ton coil that was about 5 inches longer then the current unit and also larger in width and height. Bottom line we decided not to put it in because of the amount of changes that has to be jury rigged and I simple did not trust what the factory supply rep was saying about the evaporator being the right size. The evaporator they sent was designed for a furnace application. Currently, the freon in the system has been adjusted so we have about a 10 degree "super heat", it is cooling and not freezing up and as far as I know we do not have liquid freon in the gas line. The HVAC service guy said that it will run ok like it is though we will have to change the freon level every we time we change between cooling and heating seasons. It looks like there are 4 things we can do. Have a service call twice a year to change the freon level, replace the air handler to a 4 ton unit, replace the heat pump to a 3.5 ton unit, or replace the entire system to the new freon. The current compressor is a 14 seer so I don't see why a new freon is worth it. I would rather change the heat pump out to a 3.5 ton unit than the air handler because than I would have a new unit. My questions are: Running the system as it is and changing the freon levels twice a year, would I expect a large loss in efficiency? Will the compressor life be dramatically decreased? Is there a problem in changing the heat pump unit to a 13 seer 3.5 ton R-22 unit to match the air handler? Can I just have them change out the 4 ton compressor with a 3.5 ton compressor with out changing any thing else, this would give me an oversize condenser attached to the heat pump?