The 2029 water heater efficiency standard
Final rule in effect (effective July 5, 2024); compliance required from May 6, 2029.
DOE adopted new efficiency standards for consumer water heaters in a final rule published May 6, 2024. Water heaters made in or imported into the US on or after May 6, 2029 must meet them. The rule covers storage and other consumer water heaters, but not gas-fired tankless (instantaneous) models. DOE notes that for certain classes of electric storage water heaters the new levels are currently met only with heat pump technology.
What the rule does
The rule amends the federal minimum efficiency, expressed as uniform energy factor (UEF), for consumer water heaters. DOE chose the level it called "TSL 2" after analyzing six options, and found it technologically feasible and economically justified.
It applies to products manufactured in or imported into the US starting May 6, 2029. Water heaters already installed in homes are not affected, and products made before that date can still be sold and installed.
What it does not cover
Gas-fired instantaneous (tankless) water heaters were handled in a separate rulemaking. That separate December 2024 rule was later withdrawn (see the tankless explainer).
Why heat pumps come up
In the rule’s discussion of comments, DOE wrote that "for certain classes of electric storage water heaters the adopted standards are currently only met through use of heat pump technology." Heat pump water heaters need more space, air volume and often a condensate drain, which matters if a replacement after 2029 has to fit a closet.
What to do now
- Find your water heater’s age from its serial number and note it in My Home.
- If an electric tank is near the end of its typical life before 2029, a like-for-like replacement is still possible until then.
- If you are planning a remodel, ask whether the space could fit a heat pump water heater later: room size, an outlet and a drain.
Federal Register documents
- 2024-05-06FR Doc. 2024-09209 · Final rule: amended standards for consumer water heaters; compliance from May 6, 2029.
- 2024-07-23FR Doc. 2024-16177 · Notification of data availability for gas instantaneous water heaters (separate rulemaking).
A plain-language summary of public documents, not legal or tax advice. Rules in this area have changed several times since 2024; the dates above are the record. Report a change we missed.