99600c1d_Collector___Solar_Water_Heater__Evacuated_Tube_Collector
[S.No] 8 [Flat Plate Collector] Collector & tank insulated with glasswool/ rockwool, absorbs moisture & gets wet during monsoons reducing the efficiency of the system [Evacuated Tube Collector] 
System hot water tank only is insulated using polyurethane insulation material which does not absorb water or moisture
Comparison between Evacuated Tube Collector & Flat Plate Collector - Solar Water Heater
Evacuated Tube Collector