Bonneville Power Administration partnered with the Electric Power Research Institute (EPRI) and Snohomish County PUD to be part of a national demonstration pilot for integrated heat pump water heaters (HPWH). 11 public utilities were selected to participate in this field test, which grew to 14 utilities.

Prepared by:  Bonneville Power Administration

Published:  October 2012

This project comprehensively draws on laboratory studies and, importantly, two previously conducted field studies. It augments the field studies by measuring water heater performance in climate zones and installation locations not previously observed. 70 sites had been previously studied in the field and this project added 50 more.

Prepared by:  Northwest Energy Efficiency Alliance

Published:  March 2, 2015

This evaluation quantified the in-situ performance of three recently-released HPWH products (General Electric GeoSpring™, AO Smith Voltex®, and Stiebel Eltron Accelera®300) through the installation and monitoring of 14 units in Massachusetts and Rhode Island for over one year.

Prepared by:  Steven Winter Associates, Inc.

Published:  June 26, 2012

This project sought to assess whether HPWHs can productively store energy and participate in demand response programs, thereby supporting the broadest application of the new efficiency standards.

Prepared by:  Northwest Energy Efficiency Alliance

Published:  September 29, 2014

Evaluation performed by: Electric Power Research Institute. While the technology itself is fairly well understood, the actual performance of HPWH systems has not been quantified in sufficient numbers. This demonstration aims to provide that quantification. The variation of system efficiency with climate, water usage, and installation location are being examined.

Prepared by:  ACEEE Summer Study on Energy Efficiency in Buildings

Published:  2012

Performance Research Type:  Research Study

This paper explores the laboratory performance of five integrated Heat Pump Water Heaters (HPWHs) across a wide range of operating conditions representative of US climate regions. Laboratory results demonstrate the efficiency of this technology under most of the conditions tested and show that differences in control schemes and design features impact the performance of the individual units. These results were used to understand current model limitations, and then to bracket the energy savings potential for HPWH technology in various US climate regions. Simulation results show that HPWHs are expected to provide significant energy savings in many climate zones when compared to other types of water heaters (up to 64%, including impact on HVAC systems).

Prepared by:  National Renewable Energy Laboratory

Published:  February 2012

This HPWH demonstration examines the overall performance of HPWHs installed in a conditioned space with a number of supply and/or exhaust ducting configurations, as well as the interactions between the HPWH and the home's heating/cooling system.

Prepared by:  Pacific Northwest National Laboratory

Published:  July 2014

Using the measurement and verification (M&V) plan developed by Ecotope to assess heat pump water heaters (HPWH), the AO Smith Voltex was evaluated at the National Renewable Energy Lab. This report is the third of three preliminary assessments of three different equipment models.

Prepared by:  Bonneville Power Administration

Published:  July 12, 2011

Using the measurement and verification (M&V) plan developed by Ecotope to assess heat pump water heaters (HPWH), the Rheem Hybrid HP50 was evaluated at the National Renewable Energy Lab. This report is the second of three preliminary assessments of three different equipment models.

Prepared by:  Bonneville Power Administration

Published:  July 12, 2011

This project describes market conditions, assesses barriers such as product availability, and presents options to increase participation in PG&E's residential water heater program.

Prepared by:  Pacific Gas and Electric Company

Published:  November 15, 2012