DOE Publishes Final Rule Increasing Water Heater Efficiency Starting in 2029

The Department of Energy (DOE) has finalized a new energy efficiency standard for multiple classes of residential water heaters. The rule was published in the Federal Register on May 6, and EPCA requires a five-year delay before compliance is required; this means any covered residential water heater manufactured after May 6, 2029, must meet the new standards. The covered product classes of residential water heaters include:

• Gas-fired Storage Water Heaters

• Oil-fired Storage Water Heaters

• Very Small Electric Storage Water Heater

• Small Electric Storage Water Heater

• Electric Storage Water Heaters

• Tabletop Water Heater

• Instantaneous Oil-fired Water Heater

• Instantaneous Electric Water Heater

• Grid-Enabled Water Heater

DOE is not finalizing a new standard for gas-fired instantaneous water heaters. This decision was made based on comments submitted in opposition to requiring the product class to move to condensing-only products. However, this rule includes all other consumer water heaters.

This rule is also the first water heater rule to be written for the Uniform Energy Factor (UEF) efficiency measurement. The UEF rating, a new and more comprehensive measure of efficiency, is required for each product class. It is based on the effective storage volume and the tested draw pattern to determine the unit’s efficiency. The tested efficiency must be greater than the UEF adjusted by the unit’s effective volume.

The proposed efficiency standard would have required all gas-fired instantaneous water heaters to move to condensing technology. However, DOE did not finalize a standard for that product class, and non-condensing units remain eligible for all gas-fired product classes under the final rule.

Below is the new standard for residential water heaters beginning on May 6, 2029:

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