Use Low-Flow Fixtures

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Water streaming from shower head
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Summary

Low-flow fixtures reduce GHG emissions by reducing the volume of hot water used and therefore reducing the emissions from the energy used to heat that water. Reduced water usage also leads to fewer emissions from treating and pumping water for domestic use. Low-flow fixtures are low-cost and simple to install. They generate utility bill savings for households and support sustainable water resource management. Modern quality low-flow fixtures have resolved many of the performance issues of earlier versions. Even with significant adoption, however, the total emissions reduction potential for low-flow fixtures is relatively small. We conclude that, despite its modest emissions impact, Use Low Flow Fixtures is “Worthwhile” due to its relative ease, low cost, and additional benefits.

Description for Social and Search
Low-flow fixtures reduce GHG emissions by reducing the volume of hot water that is used and therefore reducing the emissions from the energy used to heat that water.
Overview

What is our assessment?

Based on our analysis, using low-flow fixtures is a cost-effective strategy for reducing water consumption, but has only a modest impact on GHG emissions. Therefore, this climate solution is “Worthwhile.

Plausible Could it work? Yes
Ready Is it ready? Yes
Evidence Are there data to evaluate it? Yes
Effective Does it consistently work? Yes
Impact Is it big enough to matter? No
Risk Is it risky or harmful? No
Cost Is it cheap? Yes

What is it?

Low-flow fixtures lessen the total consumption of water by reducing flow rates through a household faucet or shower. Less hot water use means fewer emissions from the energy source used to heat the water, and it also means fewer emissions from pumping and treating tap water. Heating water for showers, sinks, and other domestic appliances is often the second largest source of emissions from buildings after space heating. Modern low-flow showerheads can produce comparable pressure and coverage to traditional showerheads through aeration and/or laminar flow. Aerators for faucets and low-flow showerheads are relatively low-cost investments that users can install themselves.

Does it work?

Low-flow fixtures reduce emissions from heating, delivering, and treating water by reducing hot water consumption. There is ample evidence for water savings with low-flow fixtures, as well as for the linkage between quantity and source of energy used for water heating and GHG emissions. Additionally, there is substantial research on the emissions from treating and pumping water, which can be reduced through water conservation. Low-flow fixtures are readily available, and performance labels are available to help consumers select quality products.

Why are we excited?

Low-flow fixtures conserve water, which reduces emissions, reduces energy demand, saves consumers money, and helps with sustainable water resource management. Households that adopt low-flow fixtures can enjoy significant utility bill savings because these fixtures reduce both water consumption and the energy used to heat water in the home. Faucet aerators also produce a smoother water stream with less splashing, and along with low-flow showerheads, are low-cost and simple to install. Household water conservation practices, such as low-flow fixtures, can help with regional sustainable water resource management and defer infrastructure expansion projects. This is particularly important in areas where water resources are increasingly strained due to climate change, growing populations, and other factors. In some regions, community water conservation efforts have had measurable impacts on water treatment costs, resulting in lower water rates for consumers.  

Why are we concerned?

Even with widespread adoption, low-flow fixtures would have a relatively small impact on GHG emissions. Moreover, the low cost and ease of replacement mean that low-flow fixtures can be easily reverted to less efficient fixtures, eliminating the emissions impact and other benefits. Lastly, although modern quality low-flow showerheads are comparable to traditional fixtures, the poor quality of early low-flow showerheads may have contributed to decreasing levels of adoption in some areas.

Solution in Action

Alliance for water efficiency. (2017). Conservation keeps rates low in Tucson, Arizona. Link to source: https://allianceforwaterefficiency.org/wp-content/uploads/2017/06/AWE_Tucson_ConsRates_FactSheet_final.pdf

Dieu-Hang, T., Grafton, R. Q., Martínez-Espiñeira, R., & Garcia-Valiñas, M. (2017). Household adoption of energy and water-efficient appliances: An analysis of attitudes, labelling and complementary green behaviours in selected OECD countries. Journal of Environmental Management, 197, 140–150. Link to source: https://doi.org/10.1016/j.jenvman.2017.03.070

Environmental protection agency. (2022). WaterSense performance overview: Showerheads. Link to source: https://www.epa.gov/system/files/documents/2022-05/ws-products-perfomance-showerheads.pdf

Kenway, S. J., Pamminger, F., Yan, G., Hall, R., Lam, K. L., Skinner, R., Olsson, G., Satur, P., & Allan, J. (2023). Opportunities and challenges of tackling Scope 3 “Indirect” emissions from residential hot water. Water Research X, 21, 100192. Link to source: https://doi.org/10.1016/j.wroa.2023.100192

Maas, A., Puri, R., & Goemans, C. (2024). A review of residential water conservation policies and attempts to measure their effectiveness. PLOS Water, 3(8), e0000278. Link to source: https://doi.org/10.1371/journal.pwat.0000278

Paraschiv, S., Paraschiv, L. S., & Serban, A. (2023). An overview of energy intensity of drinking water production and wastewater treatment. Energy Reports, 9, 118–123. Link to source: https://doi.org/10.1016/j.egyr.2023.08.074

Pomianowski, M. Z., Johra, H., Marszal-Pomianowska, A., & Zhang, C. (2020). Sustainable and energy-efficient domestic hot water systems: A review. Renewable and Sustainable Energy Reviews, 128, 109900. Link to source: https://doi.org/10.1016/j.rser.2020.109900

Tomberg, L. (2024). Resource conservation through improved efficiency, behavioral change, or both: Willingness to pay for (smart) efficient shower heads. Resources, Conservation and Recycling, 203, 107387. Link to source: https://doi.org/10.1016/j.resconrec.2023.107387

Yateh, M., Li, F., Tang, Y., Li, C., & Xu, B. (2024). Energy consumption and carbon emissions management in drinking water treatment plants: A systematic review. Journal of Cleaner Production, 437, 140688. Link to source: https://doi.org/10.1016/j.jclepro.2024.140688

Zhou, Y., Essayeh, C., Darby, S., & Morstyn, T. (2024). Evaluating the social benefits and network costs of heat pumps as an energy crisis intervention. iScience, 27(2), Article 2. Link to source: https://doi.org/10.1016/j.isci.2024.108854 

Credits

Lead Fellow

  • Heather McDiarmid, Ph.D.

Internal Reviewer

  • Christina Swanson, Ph.D.
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Action Word
Use
Solution Title
Low-Flow Fixtures
Classification
Worthwhile
Updated Date
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Zoltan Nagy
Zoltan Nagy, Ph.D.
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Zoltan Nagy
Zoltan Nagy, Ph.D.

Zoltan Nagy, Ph.D., researches intelligent energy management systems for buildings and cities. His work with CityLearn, an open-source platform for energy modeling, helps communities reduce their carbon footprint through smarter grid interaction.

With a background in mechanical engineering, Nagy focuses on practical applications of artificial intelligence for sustainability, developing tools that help buildings use energy more efficiently while maintaining comfort. His research bridges academic innovation with real-world implementation, contributing to climate solutions in the built environment. He holds an Msc and a PhD in Mechanical Engineering from ETH Zurich, Switzerland.

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