Evacuated tubes offer the most efficient way to heat water. Traditional flat plate solar collectors lose much of their heat to the cold air during the cooler days and nights.
The evacuated tubes are more resilient to hail and dirt as it glances or rolls off the curved surface rather than hitting or sticking to a flat surface.
The vacuum also allows the solar system to operate at below freezing temperatures. Many flat plate solar collectors have to pump hot water through the collector to stop it from freezing and cracking as temperatures approach zero, using more energy in the pump and losing much of the hot water gained during the day.
For more information visit the Solus Website.