Residential Water Heater Sizing Measure Package Support

Currently, incentives for energy efficient water heater retrofits require a like-for-like replacement. However, there is anecdotal evidence that contractors upsize heat pump water heater replacements relative to existing gas water heaters. This project adds to current statewide water heating measure offerings by allowing incentives for non-like-for-like size replacements. Heat pump water heaters consume very minimal energy compared to alternatives. The larger the tank, the larger the possible thermal battery and load shifting potential rendering restrictions on incentives based on tank size counter-productive. The expected outcome of this project is a more energy efficient installed base of residential water heaters. This project provides the new analysis and data required to support a future water heating measure package development effort that will deliver the expected outcome. We will utilize data from existing fuel substitution workpaper development and an existing CPUC-approved water heater energy use calculator with prototype buildings and various water heater sizes to model energy consumption across the CA climate zones. From a programs standpoint, there is no need for a unitary heat pump sizing tool, only like-for-like baselines for savings claims. In addition, we will conduct a survey of contractors to quantify the impact of the proposed offering. These data will support the measure package.