Introduction
Water heating is one of the largest energy uses in a California home, and the 2022 Title 24 Building Energy Efficiency Standards dramatically raised the bar for water heating efficiency. For most new residential construction, the 2022 standards have made heat pump water heaters the practical standard — not just an option.
This post explains what the 2022 Title 24 water heating requirements are, why heat pump water heaters became the default compliance path, and when HERS verification applies to water heating systems.
What the 2022 Standards Require
The 2022 Title 24 standards significantly increased the energy efficiency requirements for water heating in new residential construction. The prescriptive path sets efficiency thresholds that are most easily met by heat pump water heaters — conventional gas and standard electric resistance water heaters typically require additional measures (such as demand recirculation systems) to comply.
In practice, heat pump water heaters have become the primary compliance path for new single-family and low-rise multifamily construction. A heat pump water heater moves heat from the surrounding air into the water tank rather than generating heat directly — making it two to three times more efficient than a conventional electric resistance heater and substantially more efficient than gas on an energy cost basis.
The 2022 standards also include requirements for electric panel capacity and dedicated circuits to support heat pump water heaters, recognizing that new construction must be wired to accommodate them.
Why Heat Pump Water Heaters Became the Default
The shift toward heat pump water heaters under the 2022 standards reflects two overlapping goals. First, the efficiency requirements were raised high enough that conventional gas water heaters — which have a UEF typically in the 0.6 to 0.7 range — struggle to meet the required thresholds without adding a demand recirculation system and other efficiency measures. Heat pump water heaters, with UEF ratings typically in the 3.0 to 4.0 range, exceed the requirements by a wide margin.
Second, California's energy policy is moving toward electrification. Heat pump water heaters are an all-electric appliance that works well with California's increasingly renewable electricity grid. California's broader electrification goals — including its all-electric new construction policies in many jurisdictions — have pushed water heating in this direction.
Some projects can still use gas water heating by combining it with a demand recirculation system and meeting other efficiency conditions on the CF1R. However, the compliance pathway is narrower, and many energy consultants and builders have shifted to heat pump water heaters as the simpler all-in-one solution.
Sizing and Installation Considerations
Heat pump water heaters require more installation planning than conventional tank water heaters. They work best in spaces with adequate air volume — generally at least 700 to 1,000 cubic feet — because they pull heat from the surrounding air. In tight mechanical rooms or small closets, they can short-cycle and lose efficiency.
They also produce cool, dehumidified air as a byproduct of heating the water. In conditioned spaces, this has a slight cooling effect in summer (which can be beneficial) but adds heating load in winter. Installers should consider the location carefully to minimize energy impact.
Heat pump water heaters operate at a lower noise level than many mechanical systems but are not silent. Locating them in garages, utility rooms, or other areas where noise is less of a concern is generally preferable to installing them adjacent to bedrooms.
HERS Verification of Water Heating Systems
Not all water heating systems require HERS verification, but some do. Water heating measures that may require HERS field verification include demand recirculation systems (when a recirculation pump is used to reduce hot water waste, the pump controls and sensor systems may require HERS verification), central water heating distribution systems in multifamily buildings, and solar water heating systems when they are part of the compliance pathway.
The specific measures that require HERS verification for your project are listed on the CF1R. Review this document with your energy consultant to understand what verification your water heating system will need.
What to Tell Your HVAC or Plumbing Contractor
When specifying a heat pump water heater for a new California project, confirm the specific model number matches the unit specified on the CF1R before ordering. The CF1R lists the minimum UEF or EF required — the installed unit must meet or exceed this specification. If you substitute a different model, the CF1R must be revised before HERS verification.
Confirm that the electrical panel has sufficient capacity for the heat pump water heater's dedicated circuit. The 2022 standards include provisions for panel capacity, but real-world installations sometimes reveal gaps in planning.
Conclusion
Heat pump water heaters are now the standard compliance path for water heating under California's 2022 Title 24 standards. Their high efficiency easily clears the new thresholds that most conventional water heaters cannot meet. For builders and contractors working on new California construction, understanding the installation requirements and planning for HERS verification where it applies will make for a smoother path to permit final.