The expected rapid increase in natural gas prices as a result of deregulation and the decrease in the cost of solar energy as a result of improvements in solar energy technology will make solar more competitive with natural gas as an energy source for residential space conditioning. Systems that can combine the advantages of solar with natural gas may be the most competitive.

This paper quantifies and projects overall performance and energy costs for several combined residential solar/gas systems through the year 2000. Integrated solar/gas technologies being developed by both DOE and the gas industry are characterized and evaluated. The economic attractiveness of solar/gas systems to the gas consumer is analyzed on a regional basis to determine which systems will be the most attractive for each region. The economic feasibilities of the most economically attractive solar/gas systems are analyzed to determine when each system will become competitive with an advanced residential system consisting of a gas-fired, pulse-combustion, condensing warm air furnace and a variable-speed, vapor-compression, electric air conditioner.