A parametric analysis of the thermal design of a generic large office building with respect to building lifecycle cost is presented. Thermal systems investigated consist of building envelope construction; heating, ventilating, and air-conditioning (HVAC) operating strategies; and secondary and primary HVAC equipmenL The effect of different climatic conditions is investigated by analyzing building performance at four representative locations. To provide a range of typical energy costs, four different utility rate structures are used in the economic evaluation for each of the locations. Presented are graphical results for all "life-cycleocost-sensitive" parameters and a simple linear equation for the building thermal design life-cycle cost as a function of the continuous parameters analyzed.