Solar hot air heating is a low-tech way to provide a degree of backup heat, not a replacement for primary heating in our climate. However, it does help.

I've been watching an installation of solar hot air on a home in Bolton. It uses panels made in Methuen by a local company. Their website is http://environmentalsolarsystems.com/. In this particular house, the company made a roof dormer with four panels on it, ductwork to connect the panels in parallel to a fan pulling air from the coldest room downstairs, and ducts sending the hot air to the living/dining rooms. The fan could easily be run off a small solar panel if desired.

This is meant as "auxiliary heating" and the owner said it could make up for perhaps a quarter of the home's heating needs. We met company president Paul Soucy who came out to the Bolton home to speak with a number of us as well as to oversee installation. I have pictures (they are large files) and will see about getting something on the forum for others to see.