Gary Reysa is a retired airplane product development engineer who lives in the "Big Sky" country near Bozeman Montana. His website Build it Solar has plans, tools, and information to help you build solar projects that save money and reduce pollution. Projects are low cost designs for the do it you selfer. Some of the projects featured on the home page are for a thermal storage wall, building a sun space, plans for passive solar homes, how he is coming on a plan to cut his own energy consumption in half, ten energy saving projects with one year paybacks and a solar space heater.
The simple and inexpensive passive solar space heater that he uses to heat his shop/barn is a project that could be completed in a weekend. The design can be adapted to suit a wide variety of spaces, including a living space.