drdawg said:Passive solar is great BUT you will need an large space to build one on.
Yes, it needs to be a pretty good size in order to work properly. Mine is probably going to be the same size as shown above: 24x12x12.
drdawg said: On cold, cloudy days, even here in the deep south, there would be little if any heating of that water, so how do you maintain heat when the outside temperature is in the 20's? Just asking.
A few things:
1) A passive solar greenhouse is glazed on only one side. The other 3 sides are solid walls with insulation. So there is way less heat loss through those walls.
2) On prolonged cloudy and cold days, you use curtains on the glazed walls to provide even more insulation.
3) In extreme circumstances, you use an extra heat source. Some build rocket mass stoves, others just use propane or electricity.
