This work explores the opportunity to improve the thermal performance of a water-in-glass evacuated tube solar water heater with the aid of diffused corrugated reflector (DCR). The experiments were conducted from 6 AM to 6 PM on sunny days at Coimbatore. The water temperature has been observed for the two cases, one with a commercially form of water -in-glass evacuated tube solar water heater (WG-ETC) without DCR and another case is with the aid of DCR. The DCR has been incorporated at the bottom of the evacuated tubes in order to expose the bottom of the tubes to the diffused radiation reflected by the DCR. The water temperature in the tank gradually increases and attains the considerable temperature at the evening when there is no draw off during the day time in both the cases. Still, the integration of DCR showed the 

greater improvement in tank water temperature to the substantial value. Further the DCR enhanced the net solar gain of the system by providing the additional diffused radiation to the system. The temperature of the tank water of WG-ETC was increased 8.3°C with the integration of DCR.