Hi, I am currently adding two additions to my raised ranch in NY. I have spray foamed all walls and attics and have high end windows and doors. My current heat is electric baseboard and i have no central A.C.

I am trying to decide weather to install an A.C. only unit or a Heat Pump. My questions are:Does the fact that all ductwork will be in attic ( ceiling registers ) reduce the winter efficiency of the heat pump vs being in the floor?. I understand there is an outside thermostat that can be used with a gas furnace to switch off the heat pump below a set temperature, but how would something like that work with electric baseboard? Would the heat pump simply shut off at say 35 degrees and the room t-stats take over? Or is there another way to combine the two heat sources automatically? Any help would be appreciated.