One way of alleviating the energy shortage is the utilization of nonconventional energy sources to satisfy a portion of the total national energy demand. Since solar energy is of relatively low intensity compared to other energy sources currently employed, it seems logical to attempt to apply solar energy to satisfy low-temperature energy demands,. such as space heating and domestic water heating (Ref I) which account for approximately 22 percent of the total energy use in the United States (Ref 2).

As part of a research project on conservation and better utilization of energy performed at the National Center for Energy Management and Power of the University of Pennsylvania, (supported by National Science Foundation, Research Applied to National Needs, Grant Nos. GI-27976 and GI-29729) a detailed investigation into solar heating of residences was performed (Ref 3). This paper presents the procedures used to determine the system performance and the seasonal variation of the amount of fuel saved by solar augmentation of a spaceheating system.