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With this short video program General contractor Peter Brown describes an innovative owner built residential solar air heater on a garage in Bozeman, Montana. This solar air heater takes advantage of this garage’s very large south facing wall. The simple passive thermo-siphon design uses only the buoyancy of heated air to create circulation through the collector.



How it’s built

This collector is a series of 4’ wide 2-by-6 frames attached to the side of the building. A series of vents are cut thru the wall into the building at both the top and bottom of each frame. Within each 2×6 frame a strip of common black aluminum window screen material is suspended. This black vinyl screen acts as an absorber to capture the heat energy from the sun. Clear corrugated polycarbonate panels cover the frame and screen to provide an airtight exterior seal over the solar air heater.

How it works

Sun light passes thru the clear panels, and is absorbed by the aluminum screen. The air around the screen warms, expands, and rises, creating convection current. The vents that pass through the wall at the top and bottom of the solar air heater to allow air from within the building to circulate through it. Cool air enters the lower vents, is heated by the absorber while it rises to the upper vents where it returns to the interior of the building, as much as 80 degrees warmer. Air circulation continues as long as the sun shines on the collector, and the sun does all the work – there are no moving parts to wear out. Simple back-flaps automatically prevent reverse airflow at night or on cloudy days. During summer, the higher angle of the sun means no unwanted heat is created.  During winter in our sunny climate these heaters work exceptionally well and are augmented by reflection of sunlight off the snowy ground in front of the collector.

Readily available components

The homeowner was able to build this heating system using common materials that are readily available in local hardware stores. He was able to build and install it in about three working days.

Energy savings

With the aid of data-logging equipment the homeowner monitors the energy produced by the solar air heater and concludes that it produces about $350-400 worth of heat per winter! With this simple technology you can heat arenas, barns, workshops, garages, commercial and industrial spaces or even your home with free heat from the sun