I agree with HKestenholz about the mismatched coil and AC unit. It is like buying a Ford car, but putting a Mazda engine with a Honda transmission. You should not beleive your builder and insist on having a matched AC unit and coils, so everything works fine, and keeps on working longer. To give you an example, I bought a house last summer, and when the heating season started, I noticed problems with the furnace as it would not stop, even with the thermostat removed from the wall!! It turned out when they retrofitted the heat pump to the Dettson furnace, they kept the old controls for the furnace, and the relay switch in the furnace stayed energized, thus commanding the blower in the furnace to stay on. Since an HVAC contractor installed the proper Dettson controls, I have no more problems. I think you should buy a good unit yourself, even though it is more expensive. It will last you longer, so you will recover this money eventually. And like HKestenholz stated the other day, all major brands are pretty similar, so it is more the quality of the installation than the brand of the unit that will ensure you a good dependability over the years. I hope this helps!