1. Water heaters (a) Definition of water heater Section 321 of the Energy Policy and Conservation Act ( 42 U.S.C. 6291 ) is amended by striking paragraph (27) and inserting the following: (27) Water heater (A) In general The term water heater means a product that utilizes oil, gas, or electricity to heat potable water for use outside the heater on demand, including— (i) storage type units that heat and store water at a thermostatically controlled temperature, including— (I) gas storage water heaters with an input of 75,000 Btu per hour or less, including heat pump type units that meet the current and voltage limits under clause (iii); (II) oil storage water heaters with an input of 105,000 Btu per hour or less; and (III) electric storage water heaters with an input of 12 kilowatts or less, including heat pump type units that meet the current and voltage limits under clause (iii); (ii) (I) instantaneous type units that heat water but contain not more than 1 gallon of water per 4,000 Btu per hour of input; and (II) in the case of— (aa) gas instantaneous water heaters, have an input of 200,000 Btu per hour or less and are designed and marketed to provide outlet hot water at a thermostatically controlled temperature of less than 180 degrees Fahrenheit; (bb) oil instantaneous water heaters, have an input of 210,000 Btu per hour or less; and (cc) electric instantaneous water heaters, have an input of 12 kilowatts or less; (iii) heat pump type units (including add-on heat pumps, integrated heat pumps with storage, split-system heat pumps that consist of a separate heat pump and storage tank that are designed and marketed to operate together, and all ancillary equipment, such as fans, storage tanks, pumps, electric resistance heating elements, or controls necessary for the device to perform its function) that— (I) have a maximum current rating of 24 amperes at a voltage not greater than 250 volts