In a hot, arid zone, the load imposed on the building due to the roof is more than that for all the four walls; one of the proposed solutions to this condition is to use the roof pond. Using roof pond can reverse the performance of roof from heat source to heat sink that can withdraw the heat from building envelope. In this work a mathematical model, using the complex Fourier series was built for a single space building. Ambient temperature, solar radiation, and sol-air temperature have been treated as a periodic function of time. The effect of roof pond on the indoor temperature, heat flow to the building, temperature distribution through walls and roof were studied, as well as an exergy analysis to the roof pond was achieved. The result showed that using roof pond can reduce the mean indoor temperature by about 4°C as compared with a building using the traditional roof. The exergy analysis showed that the maximum exergy efficiency conjunct with the maximum exergy destruction through roof pond