What size collector is necessary for thermal energy storage in solar air heaters? What is the practical approach to use this system for heating one’s own house? — S. Ranjit, Punjab, IndiaSeveral systems are sold in the United States, Greece, Israel and Australia. A few here in the U.S., specify size. Of course, it all depends on the availability of sunlight and location, orientation of collectors, and overall heating needs. Cansolair forced convection solar air heaters cycle the home’s air through the solar air collector, boosts up the indoor temperature of the air by as much as 55 degrees (F) and then blows that air back into the home. The solar collectors are glazed with a special UV resistant polycarbonate that allows the collector to boost the indoor temperature no matter what the temperature is outdoors. Cansolair recommends one collector per 1000 square feet of home or office space. Another product, Solarsheet, The Solarsheat G has a hardened glass glazing and boosts the temperature of the indoor air with unit life expectancy from 25 to 30 years. Solarsheet advises that ‘one’ unit is recommended for 750 to 1000 square feet of home space. Conserval’s Solar Wall transpired solar kit (SW-100-4), has four panels to heat 1500 square feet. As I have suggested in an earlier Q&A on this subject, these systems are under-appreciated. They can be tied to ground-coupled heat pumps, wood pellet and other biomass or propane stoves and heaters, so the building has absolute assured heating — anytime and anywhere. — Scott Sklar Scott Sklar, founder and president of The Stella Group, Ltd., in Washington, DC, is the Chair of the Steering Committee of the Sustainable Energy Coalition and serves on the Boards of Directors of the Sustainable Buildings Industry Council, the Business Council for Sustainable Energy, and the Renewable Energy Policy Project.