[red-beard]

When I was taking my Solar energy course in College (1987) we proved it was not cost effective. BUT the modeling programs showed that super insulation (R-50 walls, R-100 ceilings) and window/roof overhang design at the time of construction were EXTREMELY cost effective.

If you have the space for extra wide walls, go super insulation. Then go for 2 x triple pane windows. The house needs to be completely air-tight. These days this can be done with closed cell foam.

The heating/cooling system is then significantly downsized. The biggest issue becomes humidity control. You also need to add an air to air heat exchanger to vent the house and bring in fresh air. You need several exchanges per day.

You need to add thermal mass to the house. It can take the form of a large part made from brick/stone. It can also be heavy wood beams or tanks of water.

I have been designing a country house for myself and my wife. The only other thing I'm planning is an outdoor kitchen, to keep the heat out of the house.

Houses like this in Western NY generally did not need the heating operating in most of the winter. The appliances and body heat were generally enough.