Right-sizing Water Distribution Pipes and Water Heating Systems
Results
- The Peak Water Demand Calculator (WDC) used to size water pipes resulted in lower construction costs and operational cost savings.
- The WDC also led to faster delivery of hot water to unit occupants.
- Faster and more efficient hot water delivery reduced water and energy waste in the buildings studied, which in turn lowered carbon emissions and improved water quality.
Highlights
Objectives
Investigate opportunities to reduce energy use and construction costs in new residential multifamily buildings via best practices for right-sizing water distribution pipes and water heating systems
Scope
Evaluated the WDC from the 2024 Uniform Plumbing Code (UPC) Appendix M, comparing its performance against the traditional water supply pipe-sizing method in four Minnesota multifamily buildings.
Benefits
Results showed that the WDC method consistently designed for water demand flow rates much closer to actual usage than the traditional method, which overestimated flow rates by up to 25 times.
This factsheet summarizes the project goals and key findings of this CARD-funded project seeking to validate and apply the peak water demand calculator (WDC) for water supply pipe sizing in Minnesota multifamily buildings and support the adoption of the UPC Appendix M into the Minnesota plumbing code. The team found that traditional methods overestimated peak water flow by up to 25 times as much, leading to significantly oversized pipes, while design flow rates calculated from the WDC were only 2–6 times larger than the observed peak flow rate. If the WDC is used in place of the standard practice design in 30% of new multifamily buildings, it would save the State of Minnesota an estimated 1.4 million gallons of water and prevent 141 metric tons of CO2e carbon emissions each year.
This project is led by 2050 Partners and supported by a grant from the Minnesota Department of Commerce, Division of Energy Resources, through the Conservation Applied Research and Development (CARD) program.