President Joe Biden’s proposed energy efficiency standards for water heaters, released July 21 by the Energy Department, not only would raise the cost of water heaters for consumers but take certain products off the market. One popular tankless natural gas water heater, made by Rinnai in Griffin, Georgia, would have to be discontinued. The public has until Sept. 26 to file comments. Beginning in 2029, the Energy Department’s proposed regulation would set government standards for all types of water heaters, including gas-fired, oil-fired, electric, and instantaneous tankless water heaters. The proposed rule would raise standards disproportionately for tankless, gas-fired water...