Forgoing cold-weather heat pumps in dual-fuel steam heat system?
My family is considering purchasing an older (~1907) home in coastal New England. It is about 1,800 square feet, two levels, all discrete rooms (no open floor here!) No air-conditioning, and we're planning on a full MassSave inspection and expecting it to need a lot of new windows and insulating.
The current heat system is steam heat using a new (2021) natural gas fired boiler and big cast iron radiators. The system is in good working order, and natural gas is cheap, so I'm not inclined to rip them out day one!
Ideally I'd love to make it an all-electric home, but other repairs may take priority. It only has 100 amp service, but the only other big draw is an electric drier, so there may be some capacity for a couple heat pumps with some smart-panel upgrades.
If we went forward with a dual fuel system, would it make sense to forgo more expensive low-temp heat pumps (like the Mitsubishi hyper-heat) and just set the crossover point at a relatively high temp like 30-35 degrees? Or is that a penny wise and a pound foolish, and if I'm planning on going heat-pump only in the future, just grab ones capable of heating the house entirely even in a cold snap (even though initially I'd only be using the gas heat most cold days).
Finally, if you could only do one floor without a panel upgrade, would you do the first floor (heat rises) or second (real AC in the summer when sleeping)?