The dew phenomenon of ambient air is considered the major problem associated with solar air heater when thermal energy storage is used. The current research was mainly conducted for solving this problem. This was simply achieved by covering the upper side of the heater by insulated cover during the night period. For this purpose the v-corrugated solar air heater integrated with phase change material (PCM) as the most efficient heater as reported in the literature was constructed and tested with and without using insulated upper cover during night. When the insulated upper cover was used during night, a significant increment in glass cover temperature was found. In addition, the absorber plate and the PCM temperatures were slightly higher than their corresponding values obtained without using insulated upper cover. It is also found that the use of the insulated upper cover during night increases the outlet air temperature and daily average efficiency by 2-4 °C and 6.6%, respectively. It is also concluded that the heater operation time increases by 1.5 hrs when the insulated upper cover is used.