Due to influence of ground temperature the greenhouse room temperature increases and its relative humidity decreases. In the Fig. 6 it can be observed that the temperature of solar collector was always higher than ambient, inside room temperature for both cases. For Case-I maximum ground temperature was 69.4 °C,73.3 °C & 56.2 °C where as the maximum ambient temperature was 45 °C, 45.8 °C & 40.4 °C. For Case-II maximum ground temperature was 56.2 °C, 55.7 °C & 46.4 °C while the maximum ambient temperature was 38.9 °C, 40.3 °C & 37.3 °C. In terms of percentage, rise in temperature of the solar collector was 19.91%, 21.1% and 13.38% for day 1, day 2 and day 3 respectively which is showing the effectiveness of solar collector placed inside the NWIGHD. The rise in temperature inside the greenhouse is a combined effect of solar collector and insulated north wall. It is justified that the use of solar collector inside the dryer can improve the dryer performance and minimise the heat loss. The increased temperature inside the NWIGHD will help the system for faster rate of moisture removal process. The difference of inside room air temperature of NWIGHD and modified greenhouse dryer is 2.8 °C which is 14% higher than the modified greenhouse dryer (Prakash and Kumar, 2015).