Electric demand water heaters were tested in two homes and compared<br />to customers' existing gas and electric storage water heaters. Findings:<br />� The demand water heater will save the tested customers about 50<br />per year compared to their storage electric water heaters. � The<br />savings was equivalent to the storage water heater's standby loss.<br />� The electric demand water heater was nearly twice as expensive<br />to run as the gas water heater at local utility rates. � Both test<br />participants were satisfied with the hot water service provided by<br />the demand water heaters. Neither customer used hot water at more<br />than three gallons per minute, about the limit at which most demand<br />heaters can fully heat the water. � Demand water heaters are more<br />expensive than storage water heaters�the test units cost about 500<br />to 800 (retail). Installation of the test units costs another 800<br />to 1200 at each site. [ABSTRACT FROM AUTHOR]
Johnson, R. K., & Clark, C. A. (2006). Field evaluation of two demand electric water heaters. In ASHRAE Transactions (Vol. 112 PART 1, pp. 426–435).