Residential space heating cost: geothermal vs conventional systems

The operating characteristics and economies of several representative space heating systems are analyzed. The analysis techniques used may be applied to a larger variety of systems than considered herein, thereby making this document more useful to the residential developer, heating and ventilating contractor, or homeowner considering geothermal space heating. These analyses are based on the use of geothermal water at temperatures as low as 120/sup 0/F in forced air systems and 140/sup 0/F in baseboard convection and radiant floor panel systems. This investigation indicates the baseboard convection system is likely to be the most economical type of geothermal space heating system when geothermal water of at least 140/sup 0/F is available. Heat pumps utilizing water near 70/sup 0/F, with negligible water costs, are economically feasible and they are particularly attractive when space cooling is included in system designs. Generally, procurement and installation costs for similar geothermal and conventional space heating systems are about equal, so geothermal space heating is cost competitive when the unit cost of geothermal energy is less than or equal to the unit cost of conventional energy. Guides are provided for estimating the unit cost of geothermal energy for cases where a geothermal resource is known to exist but has not been developed for use in residential space heating.