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Nonresidential Drain Water Heat Recovery

Measure Description

This measure would prescriptively require drain water heat recovery (DWHR) in nonresidential buildings types that are found to be cost-effective, as well as add DWHR as a compliance option for all nonresidential buildings. This CASE topic builds on a DWHR measure for low-rise residential in Title 24 2019 as a compliance credit and an alternative prescriptive path for gas storage water heaters, heat pump water heaters, and solar water-heating systems.

DWHR is an energy-saving technology used to reduce the amount of energy needed by a water heater or fixture to heat incoming water to the required temperature. The technology utilizes a heat exchanger in the drain line to pre-heat makeup water supplied to the cold-water side of a water heater or fixture. The device can be installed in either an equal flow configuration (with preheated water being routed to both the water heater and the fixture) or an unequal flow configuration (preheated water directed to either the water heater or fixture). DWHR devices are available in horizontal and vertical configurations, and both are included in this measure

Relevant Documents

Measure proposals, supporting documents, and other outside references will be made public as they become available.

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This measure description will be updated as research is developed to support the 2022 code cycle. For questions or suggestions, email Include the measure name in the subject line.

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The Statewide CASE Team values input from all stakeholders engaged in the Title 24, Part 6 code change process. We encourage the open exchange of code change comments and concerns.

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