120V HPWH Research

Active Pilot Programs and Demo Projects 120V HPWH Field Study

About the Demonstration Project

Focus on Energy is conducting a field study in Wisconsin in partnership with other Midwestern states to assess cold climate performance for 120-volt heat pump water heaters (HPWH). HPWHs use heat pump technology to heat water more efficiently than standard water heaters which include electric resistance and gas- or propane-fired water heaters. Historically, HPWHs have needed a 240-volt connection to work, which may require costly electric upgrades to a home.

120-volt HPWHs, however, claim to deliver energy-saving benefits similar to a 240-volt heat pump, but are more compact and only require a standard household outlet, making them easier and less costly to install. Because these units have a lower voltage, their hot water output can be limited, and it can take longer for water to reach the desired temperature. This project seeks to understand technological barriers, market potential, and savings opportunities of 120-volt HPWHs in Wisconsin. The project aims to evaluate the performance of 120-volt HPWHs in real homes. Through modeling and field validation, this project will provide evidence of performance for the supply chain and help design program strategies to effectively target the best applications of 120-volt HPWHs.

Project Timeline: May 2022 - December 2024
Customer Segment: Single-family residential

Demonstration Project Objectives:

Determine the household types and water heating demands a 120V heat pump water heater is best suited for.
Understand the differences in operation and installation as compared to 240V heat pump units and water heaters supplied by other fuel sources.
Identify any supply chain perceptions which could impact market adoption rates.
Demonstrate the impacts of 120V HPWHs in different residential applications, installation locations (e.g., basement, closet), and climate zones in the Midwest. In Wisconsin, have at least three installations in basements and three in closets split across the two Wisconsin climate zones.
Meter field performance and analyze data to determine:
- Hot water shortages and any problematic water usage patterns for occupant comfort, such as hot water depletion during high use times.
- Electricity consumption and energy efficiency (e.g., field energy factor) under varying conditions and hot water loads.
- Operating cost impacts, including estimating baseline gas and propane energy consumption based on models calibrated from field data.
- Potential to load shift away from peak price or emission periods.
- Estimated dehumidification effect by measuring condensate removal.

Quantify costs associated with 120V retrofits, including product, installation, and operating and maintenance costs.
Understand the perspective of the following stakeholders through surveying:
- Users: ability of the equipment to meet user needs and provide a good customer experience.
- Installers: installation lessons learned, technology limitations, and training needs.
- Manufacturers: feedback on installation procedures and technology modifications throughout installation and monitoring periods.
Determine any field limitations and opportunities of the technology.
Collect information for use in workpapers to support 120-volt HPWH as an energy efficiency measure.

Demonstration Project Objectives:

The research team conducted energy modeling, cost analysis, secondary data analysis, and supply chain research to determine the best technological applications for 120-volt HPWHs in Wisconsin. A report summarizing the findings can be found (insert link).

Eleven project sites in Wisconsin were recruited for this demonstration project among several others from other Midwestern states. Monitoring equipment and 120V HPWHs have been installed across all sites. Participant surveys have been completed with initial feedback indicating high customer satisfaction. Data collection and analysis is underway with a final project report anticipated in December 2024.

Lessons Learned

The first phase of this research included modeling 120-volt HPWHs in Wisconsin climate zones, cost analysis, secondary data analysis, supply chain research and surveying market actors. Results from this phase of this project provided the following lessons:

Equipment Performance: Modeling results suggest the 120V HPWH can supply enough water to satisfy a four to six occupant single family home in Wisconsin and can accommodate consecutive hours of 20-gallon hot water draws, which translates to two to three showers with other hot water end uses per hour.

Energy Savings: Models estimated the 120V HPWH uses 10-15% more energy than the 240V, but 43-50% less energy than natural gas or propane water heaters.

Costs and Installation: The 120V and 240V HPWH equipment can be $1,000 or more than a natural gas or propane water heater. The 120V HWPH remains more cost effective than a 240V given there is no need for a panel or amperage service upgrade. To attain similar first hour ratings, the 120V HPWH may have larger storage tanks than the unit being replaced which could increase costs.

Supply Chain Support: Distributors and plumbers remain skeptical about 120V HPWH performance without examples of successful installations in the Midwest. All supply chain actors interviewed emphasized consumer demand drives their interest in stocking or selling a given technology. As of mid-2022, two 120V HPWH models existed, and three other manufacturers planned to release products in early 2023.

Learn More

Research and Modeling Report: Final Report- December 2022
Field Study Report: A final report on the field study findings will be available at the end of 2024.

Questions?

For more information about this study, email hpwh-study@focusonenergy.com.