I am planning to build a 3300 sq ft. home. My contractor say I needed to have 2 systems to accomodate that size house.One for the upstairs and one for down. He recommended that I get a "Piggyback" system which has a heat pump with gas back up. This way when I need to just knock off the chill in the house I can just use the heat pump. But when it gets bone chilly I then could switch to the gas system. It seems like overkill because I will actually have 4 systems. I would like to know if I could just get a gas system for the down stairs and a heat pump for up stairs. Will this work and how efficient would a setup like this be compared to the split system?
Thanks in advance