Using the TRNSYS simulation program, the effect of the absorptance of external surfaces of buildings on heating, cooling and total loads has been studied. The meteorological data used in this study are for Amman and Aqaba, representing mild and hot climates, respectively, in Jordan. Two types of construction materials, namely, light weight concrete block and heavy weight concrete were used in the simulation. The effects of the absorptance on energy loads for insulated buildings were also calculated. The results show that, for not insulated buildings, as the absorptance was changed from one to zero, the total energy load decreases by 32%, while for insulated buildings, it decreases by 26% in Amman, whereas this decrease was about 47% for not insulated and 32% for insulated buildings in Aqaba.