3. Smart water: Redesigning domestic hot water systems

Workshop Date:


Non-natural gas alternatives for domestic hot water heating. Discussion topics will include single-pipe, single-temperature water for hand washing, waste to energy systems, sewage water heat recovery, and CO2 heat pumps.



'Tell me something I don't know' podcast format

Highlights on the Decarb:HEALTHCARE community - Austin Barolin


  • Travis English, Kaiser Permanente
  • Walter Jones, Metro Health
  • The audience


  • Single temp hand washing - Brian Hageman, Mazzetti
  • Waste to Energy systems - Theodora Alexakis, Terragon
  • Wastewater heat recovery - Shelbie Roberson, Mazzetti
  • CO2 Heat Pumps - Ryan Brown, Watts Water Technologies

Continued discussion on Decarb Community

Upcoming Workshops 


Thank you to all our presenters for the robust information and dialogue. And, though we see great value in this content, we feel unable to provide AIA CEUs for this specific workshop due to some of the marketing-slanted content included. We will continue to strive to provide AIA-accredited sessions, maintaining adherence to the AIA CEU provider guidelines. Thanks for your understanding.


  • Explore innovative design ideas to reduce load like single temp hand washing
  • Explore alternative methods for generating hot water (without using natural gas, heat recovery, etc.)
  • Understand safety and efficacy of various approaches related to hot water
  • Identify existing regulatory barriers to these technologies


Current State

  • Traditional design of domestic hot water systems using gas-fired boilers is inefficient.
  • Domestic hot water is often produced at 140 degrees and mixed with cold water at the fixture to produce warm water to be used for handwashing or showers. Heat is constantly lost through many small branches of hot water piping throughout the facility.
  • DHW is used and then dumped down the drain without any heat recovery.


  • Hot water is not necessary for handwashing; the CDC advises against it in a healthcare setting due to the risk of dermatitis.
  • Single temperature handwashing uses one plumbing line of 75-degree water to feed all handwashing stations / sink in a facility which will save money and materials in new hospital designs. Reducing the required capacity for hot water at handwashing stations can lead to energy savings as well.
  • Heat recovery from wastewater lines can be used to recover energy and preheat the incoming domestic hot water.
  • With preheated water, and lower overall DHW loads, alternative DHW production methods can be effective, such as waste to energy systems and CO2 heat pumps.

Call to Action

  • Pilot project opportunities here! The technologies presented in this workshop are cutting edge and have few pilot projects. If you are interested in piloting one or more of these technologies, please reach out to the decarb:Healthcare community. Additional pilot installations in a CA hospital, or other US hospital, will be critical in determining the feasibility and efficiency of these technologies in the effort to decarbonize healthcare buildings.
  • Continue to share your thoughts about these technologies at www.decarbhealthcare.com