LEED-v4 Homes EA Credit “Efficient Hot-Water Distribution System,” Option 1, awards 1 point for each qualifying distribution strategy that demonstrably reduces run-time heat losses and wasted water. The three qualifying strategies are

• limiting branch-line length via structured/loop plumbing (A),

• installing a central manifold (home-run) distribution system (B), and

• installing a demand-controlled recirculation pump that is activated only when hot water is needed (C).

Pipe insulation to R-4 is addressed elsewhere (baseline requirement or Option 2) and therefore does not earn points under Option 1.

D. Insulating all domestic hot-water piping to R-4 is a separate requirement (baseline or Option 2); it is not listed among the point-earning measures in Option 1.

1. USGBC. LEED v4 Homes Design & Construction Reference Guide, Energy & Atmosphere credit “Efficient Hot-Water Distribution System,” Option 1: Efficient hot-water distribution, bullets 1-3 (pp. 432-434, 2019 ed.).

2. USGBC. LEED for Homes 2008 Rating System, EA Credit 4 - Efficient Hot-Water Distribution, Items 4.3–4.5 (pp. 123-124).

3. J. Burch & R. Hendron, “Measured Performance of Demand-Controlled Hot-Water Circulation Systems,” NREL Report NREL/TP-550-41990, Sect. 3 (2007).

4. C. Bohac et al., “Energy and Water Savings from Home-Run Plumbing Systems,” Journal of Building Performance Simulation, 6(6): 413-422, DOI:10.1080/19401493.2013.768242, Sect. 4.2.