Water Recirculation System & Structured Plumbing 101

By: Smart Zero Home
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Smart water distribution design through structured plumbing design and water recirculation systems, can save energy, reduce hot-water wait-time, and save water. The following structured plumbing and recirculation design strategies are based on the research of the California Energy Commission engineer Gary Klein's research. Recommended strategies include:

Central Plumbing Core to minimize the distance of hot water fixtures from the water 

Trunk and Branch distribution system, with adequate Pipe Insulation. Half-loop recirculation design recommended

Multiple water heaters including smaller instantaneous/tankless water heaters for high volume demand fixtures (master bedroom, kitchen)

Recirculation products with temperature sensors. 

Recirculation System & Structured Plumbing Save Water, Reduce Hot Water Wait Time, and Save Energy

The half-loop recirculation distribution design, has a trunk and branch distribution system, and a recirculation pump with temperature sensor located equal distance (half-loop) from the central plumbing core (circle). Gary Klein's "Saving Water and Energy in Residential Water Distribution Design" discusses the current issues, potential savings, various water distribution design and possible solutions.

There are a number of recirculation pumps and complete systems readily available in the market  with options of timers and temperature sensors. The most popular options are from Metlund, ACT, and Grundfos. See our pick of the top water recirculation systems in the market today. Recirculation pumps can be used to deploy structured plumbing water distribution system in a house, resulting in increased comfort (minimal hot water wait), and water and energy savings.

The following video by Home Depot, demonstrates the installation of a hot water recirculation pump:


Also see our post on top water recirculation systems in the market today, and on Tankless Water heater 101.