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About the Study

Jim Lutz and Steven Lanzisera, in the Environmental Energy Technologies Division at Lawrence Berkeley National Laboratory (LBNL), are conducting this study to explore the efficiency of hot water distribution systems in California residences. You’ve likely had the experience of waiting for shower water to get hot? Until the shower reaches a comfortable temperature, the water goes down the drain (usually).  Both water and energy could be saved! Information about hot water use in homes will enable the development of effective conservation strategies, for both energy and water.

Project Description:

This project will monitor water use in 25 households in the Greater Sacramento Area and the Bay Area, and gas use in a subset of these residences.  We will install water flow and temperature sensors at each indoor water use and at the water heater, and some homes will have a non-invasive, whole house gas meter installed. These sensors will not interfere with residents’ use of water or gas. Whenever water is flowing, data will be wirelessly transmitted to a field client for upload to the database at LBNL.  The monitoring will continue for approximately six months. From the collected data, we will be able to calculate the efficiency of the hot water plumbing system in actual use.

Water sensors.   The water flow and temperatures sensors have been developed in collaboration with LBNL Engineering, and the sensor housing meets NSF requirements.  Water meters provide 1s flow and temperature data when water is flowing and 10s data when water is not flowing. The water flow and temperature sensor passed AMSE A112.18.1-2005 reliability testing for water fixtures, and further testing was performed at LBNL. The testing met or exceeded all applicable standards for plumbing fixtures.

Licensed plumbers will insert the sensors within the water pipeline under sinks, showerheads, clothes washer, toilet, etc. to monitor indoor water uses. In a subset of homes, a non-invasive gas sensor will measure household gas meter movement.  A field researcher will install the wireless units and a small field client computer.

Gas meter sensors.   The non-invasive gas meter reads the utility gas meter and provides real-time data (10s sample rate) over WiFi. This meter does not contact natural gas, the natural gas piping, or make any changes to the utility meter. The field researcher will install this unit if applicable.

Water meters are battery powered, and the gas meter uses a UL approved AC to DC adapter to provide power.

Duration of Study.   Participation in this study is expected to take approximately 20 hours over six months. We estimate that the installation will take approximately one day at the start of the research. At the conclusion of the study, researchers will ask the homeowner to schedule a day for removal of the sensors and metering equipment and to conduct a ten-minute follow-up interview.

Potential Benefits of Research

This project will benefit the public in a number of ways, as research results can be used for:

  • Generate data to guide the development of effective public policies to reduce energy and water use in residential water distribution systems.
  • Provide water/energy efficiency information to improve the design of residential buildings.
  • Enable the development and evaluation of effective conservation strategies in residential water distribution systems, for both energy and water.
  • Reduce home water and energy use and save money via feedback to residents.
  • Develop specific technologies to reduce water and energy use in home distribution systems.
  • Provide content for consumer information and education to reduce energy and water consumption.

If you would like to participate...

To be eligible to take part in this study, you must be at least 18 years of age, live in a home that you own in a study area with a single residential water heater, speak English in your home, and have internet access over which the monitoring system can transmit data. If you are interested in participating, submit the web form by 06.30.2013: https://www.surveymonkey.com/s/LBNLHotWaterStudy. Participants will receive $50 after monitoring system installation and an additional $50 after monitoring is completed and equipment has been removed. Please note that LBNL employees are not eligible to receive incentive.


As with all plumbing work, it is important for homeowner to monitor the plumbing work especially in the first week to make sure there are no leaks or other issues.  Feel free to contact the research team at contacts below with any questions or concerns.

For major issues: call rapid response line at 510-486-7705.  (Rapid response telephone number is on wireless modules and field client.)

General contact email list: hotwater@lists.lbl.gov.

If there is a problem with a meter, email hotwater@lists.lbl.gov.

If you want to quit the study, email hotwater@lists.lbl.gov, so that we can arrange with you to come and remove the study equipment.

If you have any question regarding your treatment or rights as a participant in this research project, please contact the Human Subjects Committee at harc@lbl.gov or (510) 486-5399.