Energy conservation options for residential water heaters

Abstract

Current designs of gas-fired and electric water heaters present a substantial opportunity for energy conservation through reductions in jacket losses, pilot losses and flue-gas losses. A systematic analysis and comparison of alternative energy-conserving designs has been carried out. Promising options for gas-fired water heaters include increased insulation, thermostat setback, forced-draft burners with intermittent ignition and flue closure, and instantaneous (low storage) designs. High efficiency electric water heaters incorporate increased insulation, thermostat setback, solar preheat, and heat pump operation. The evolution and market penetration of these alternative designs, some of which are commercially available at this writing, can reduce the energy usage for residential water heating in the U.S. by approx. 0.3 quads in the near-term, and up to 1.0 quads in the long-term as advanced designs achieve widespread saturation.