Residential Feasibility Assessment of Gas Tankless Water Heaters in PGE Service Territory
Project Number PGE 0412 Organization PG&E End-use Water Heating/DHW/HPWH Sector Residential Project Year(s) 2004 - 2007Project Summary:
Storage gas water heaters are the predominant residential water heating appliance used in Pacific Gas and Electric Company (PG&E) service territory and throughout California. Gas storage water heaters are characterized by low first cost, hot water delivery characteristics compatible with the cultural expectations of most U.S. homeowners, and lower than average seasonal efficiency compared to other gas heating appliances. Instantaneous or tankless gas water heaters have been available on a small scale for many years in this country, but have not yet achieved the widespread acceptance common to Europe and Japan. The current generation of tankless water heaters offers significant technology improvements over their predecessors. Variable burner capacity, higher heating capacities, and sophisticated controls have significantly improved delivery temperature characteristics under a range of flow rates. Elimination of standing pilotshas also significantly improved the standby performance of tankless units; tankless Energy Factors are more than 35% higher than typical storage gas water heaters.
PG&E commissioned this study to update a 2004 PG&E tankless water heater market assessment study. During the past three years there has been considerable market interest and increased research into tankless water heater performance. In the last five years an estimated 140,000 tankless units have been installed in California. Utility new construction incentives of $200 (PG&E, Southern California Gas, and San Diego Gas & Electric) and a Federal tax credit of $300 enacted in 2006 have improved the economics of these systems.