Solar home heaters or solar space heaters  are growing rapidly in the solar water heating industry. The main  reasons behind their popularity include the enormous energy efficiency  and higher operational temperatures through the solar vacuum tubes.

Generally,  solar evacuated tube collectors work well in low light conditions and  temperatures, i.e. minus 35 degrees. As a result, most homeowners in  Northern USA, Canada and Europe are using solar home heaters for heating  their homes. https://www.solartubs.com/solar-home-heating.html