Good to know about the refrigerant, I haven’t even begun to consider different types of systems.
I didn’t think about the descaling, that’s definitely something to consider. My prime consideration with them was a) save on the extra piping, b) not have to wait for hot water to arrive, wasting water in the process (mountains, it gets a bit nippy up here), c) not have to operate a circ pump. I wouldn’t necessarily mind an electric tank WH, I just thought it’d be nifty having instant hot water in each room and not worrying about the tank running empty.
And yeah since we’re building from scratch, I intend on designing the roof with to accommodate as many panels as necessary (I haven’t even begun to do the load calcs for anything yet. In a perfect world, I’d want the front of the house facing north, leaving the entire south side of the house available for solar without cluttering up the curb appeal. Since we don’t have net metering where I’m at, I also have my eye on a battery system primarily for night operation and outages (they’re frequent up here), and as essentially a whole house UPS.
In all fairness, heat pumps are stupid easy to install, and many of them come as a pre charged kit that you can do yourself. I understand not everyone wants to drill a home in the side of their house, but anyone that is handy can do one themselves in a day.