> During the daylight hours there's still more than enough total insolation to heat the small amount of air we need to inside our houses I sold solar panel for

> During the daylight hours there's still more than enough total insolation to heat the small amount of air we need to inside our houses I sold solar panel for 10 years. Both solar thermal and PV. This is simply not true. You need to greatly oversize your panels (≥6x) and also have a passive house with a huge storage buffer (>5000 liters). In the summer you end up having to pump the waste heat into a pool. There are also maintenance costs. For PV you need huge amounts of battery storage. It's simply not economical above the 40° parallel to use solar for heating. For DHW or charging your EV it's okay, but in the winter you'll get at most 1/6 the amount of heat or electricity that you get in the summer provided that the panels are not covered in snow.