The aim of this research effort was to develop a mathematical model and digital computer program for accurately calculating the energy required by residential housing units. This model was used to establish an accurate procedure for determining the monthly and seasonal energy requirements of alltypes of residential structures. The mathematical model and digital computer program developed were verified by extensive calculations and field measurements applied to nine residential dwelling units. Four of these sites have identical two-storey frame construction, one of which was unoccupied and was thus used as a control house or a minimum energy usage home. The technical aspects of the project were developed by personnel at Edison Electric Institute.