The combinations of using solar air collector and specified building envelopes were investigated in this paper. A transient heat conduction equation of building envelope was solved to obtain inner surface temperature fluctuations for different building outside temperatures. A mathematical model was developed based on numerical heat transfer method to simulate the hourly thermal performance of a novel solar air collector. Combined conditions of these two heating methods include: solar air collectors being valid or not; building envelope schemes with different heat transfer time lags and decrement factors. In the spring season of Datong city, China, hourly thermal performance of solar air collector and hourly temperature fluctuation of the inner surface of building envelope were obtained and used as the input parameters of a code which can calculate the heating load and the indoor thermal comfort. The performances under all combined conditions were compared. It was found that passive heating system consists of solar air collector and building envelope with low time lag and low decrement factor provides the best thermal comfort with the least energy consumption in all of the studied systems. The results of this study are useful for designing optimal building envelope schemes and heating ventilation systems.