You also have to deal with a ton of extra plumbing and envelope penetrations, and the space the thermal solar collector takes up doesn’t fit nicely with a solar PV array either. A HPWH might use 800 kWh/year, so thats like less than two 400+ W panels to cover all your water heating. I think thermal solar is fine tech and there are certainly situations where it makes sense (perhaps yours) but overwhelmingly HPWH is more cost effective and simpler.
You also have to deal with a ton of extra plumbing and envelope penetrations, and the space the thermal solar collector takes up doesn’t fit nicely with a solar PV array either. A HPWH might use 800 kWh/year, so thats like less than two 400+ W panels to cover all your water heating. I think thermal solar is fine tech and there are certainly situations where it makes sense (perhaps yours) but overwhelmingly HPWH is more cost effective and simpler.