We have a 14 X 70 MH with attached sun room apx 10X17. We are having our heat pump replaced. Currently have a 2.5 ton. Salesman told us we would need a 3.5 ton, and suggested a 13 SEER, 42,000 BTU. I am concerned that is too much for our small home, though the MH is an older model, 1984, and as such, not energy efficient. We live near Myrtle Beach, SC. Also, salesman said life of heat pump units where we live is only about 10 years....does that sound right? Our current unit is working, but is 10 years old, and does not cool the sun room sufficiently when it is very hot outside. Also, can a 3.5 ton replace a 2.5 ton without any modification. The salesman looked at our electric panel and said it was sufficient. I don't know enough about it to challenge what he has told us.
Thanks for any input you may have.