[SDMCF]

Originally Posted by MN Renovator

The cost of PV has dropped but water heat hasn't.

I think you have put your finger on the key point here. When I installed my solar thermal system a few years ago the economics clearly showed that was a better option than PV. A significant drop in PV prices, plus improvements in heat pump technology, has apparently changed that.

I suppose in areas other than MN where the sun shines more consistently with less snow cover it might make more sense

Snow cover is good, in the right situation. My panels are on the south-facing wall of my house and the ground slopes up to the house. At the time of year when there is snow cover the sun is very low in the sky and is reflected off a large area of snow onto my panels. I get maximum production on bright days when there is snow cover, despite there being fewer daylight hours at that time of year.

Solar hot water with integrated space heat would be an exception to this because you're likely to use more of the energy available for capture, although a system sized for that would be more of a waste in the summer unless you have a process heat use or absorption chiller.

My system provides mainly space heat. In my climate there is a relatively short period when no space heat at all is required, so this makes more sense here than somewhere with a longer summer.