A vacuum solar tube is a simple and effective energy converter, which absorbs the solar energy and converts it into heat for use via the selective absorbing coating.

Each evacuated tube consists of two glass tubes made from extremely strong borosilicate glass. The outer tube is transparent allowing light rays to pass through with minimal reflection. The inner tube is coated with a special selective coating which features excellent solar radiation absorption and minimal reflection properties. The space between the two layers of glass is evacuated and the vacuum quality is an important factor in the performance of the evacuated tubes.