RE: Docket Number EERE–2017–BT–STD–0019/RIN 1904–AD91: Supplemental Notice of Proposed Rulemaking for Energy Conservation Standards for Consumer Water Heaters

determination in the SNOPR that circulating water heaters provide the same consumer utility as storage-type water heaters and that there are no performance-related features that would necessitate establishing a separate product class for circulating water heaters. [...] As DOE notes in the SNOPR, this is evident from the June 2023 test procedure final rule for water heaters, which requires circulating water heaters to be paired with a storage tank for testing – representative of how these products would be used in the field.2 Thus, we believe it is appropriate to classify circulating water heaters as storage-type water heaters and be represented in the applicable. [...] This would mean that the new and amended storage-type water heater standards that were proposed in the July 2023 NOPR would be applicable to circulating water heaters. [...] In the SNOPR, DOE proposed to revise the definition of “circulating water heater” to designate these products as storage-type.3 Specifically, DOE’s proposed revised definition would state that “paired with a separate storage tank, a circulating water heater constitutes a storage-type water heater.” DOE notes in the SNOPR that it would be appropriate to simplify all circulating water heaters – incl. [...] As DOE notes in the SNOPR, gas-fired instantaneous water heaters provide a unique utility to consumers by meeting a continuous demand for hot water, up to the maximum flow rate.5 These products utilize a flow-activated control scheme and larger burners that allow them to meet the demand for hot water without the need for a recirculation pump and a separate stored volume of water.