In Hot Water! The Challenges and Barriers of Decarbonizing Water Heating in Multifamily Buildings: Preprint

Research output: Contribution to conferencePaper


Domestic hot water heating is responsible for 32% of the total energy consumption in multifamily buildings and offers a significant decarbonization opportunity. An extensive market assessment was conducted to understand and document key technical and economic barriers to electrification of domestic water heating in multifamily buildings throughout the U.S. Through the program, 77 interviews were conducted to understand key market drivers and technical challenges associated with electrification of water heating systems in both retrofit and new construction scenarios. Interviewees encompassed a wide range of stakeholders in the ecosystem surrounding water heating systems, including suppliers, manufacturers, designers, owners, utilities, and developers. This paper documents key interview takeaways, including an extensive list of market barriers, technical challenges, and sought-after technology attributes that can inform pertinent design criteria for electric water heating research, development, and deployment efforts. Among economics and energy efficiency features, interviewees overwhelmingly alluded to space constraints, cold air exhaust, and lack of clear guidance regarding distributed versus centralized design selections as key challenges associated with mass adoption of electric water heating. Owners and developers seek systems with minimal footprint, which maximize rentable space and profits. Moreover, distributed heat pump solutions should balance ducting costs that mitigate cold exhaust entrainment into conditioned zones. Lastly, the market needs clear guidance regarding the selection of distributed versus central electric hot water systems.
Original languageAmerican English
Number of pages16
StatePublished - 2022
Event2022 ACEEE Summer Study on Energy Efficiency in Buildings - Pacific Grove, California
Duration: 21 Aug 202226 Aug 2022


Conference2022 ACEEE Summer Study on Energy Efficiency in Buildings
CityPacific Grove, California

NREL Publication Number

  • NREL/CP-5500-82603


  • challenges of water heating electrification
  • decarbonizing water heating
  • domestic water heating
  • electrification
  • electrifying water heating
  • heat pump water heaters
  • multifamily buildings


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