The use of energy performance software will become a necessity in the early design stages to quantitatively verify the energy consumption of buildings. In this research, a simulation tool was used in designing a zero energy senior community center for an apartment complex. After comparing and evaluating case 1 (code) and case 2 (current design trend), each load element was analyzed to derive the low energy design for case 3. For case 3, the thermal performance of the insulation and windows as well as the lighting efficiency improved. In addition, photovoltaic solar power was considered as the renewable energy. For heating, the percentage of heat loss from opaque surfaces is 52%, while that from infiltration is 31% and that from window systems is 17%, demonstrating that the envelope has a significant effect on heat loss. For cooling, the percentage of heat gain due to window systems is 43%, while that due to lighting is 33%, that due to people is 17%, and that due to equipment is 7%, demonstrating that the internal and solar heat gain account for most of the energy loss, while the envelope has an insignificant effect. Photovoltaic solar panels were included as a source of renewable energy for the low energy design of case 3 to offset the heating and cooling energy consumption. It was found that using renewable energy would result in an energy surplus of 3,438kWh/year.