Advanced Hot Water Delivery Test
Hot-water delivery passes the advanced test: ≤ 0.6 gallons before delivery and +10°F temperature rise.
Spec
Applies uniformly from Platinum upward.
Scope
Hot-water distribution from the water heater (or recirculation manifold) to the farthest hot-water fixture in the home.
Requirements
Performance targets
- 01.
At the farthest fixture from the water heater, less than 0.6 gallons must be drawn before hot water arrives (measured from cold start, fixture wide open).
- 02.
Within the same draw, the temperature must rise at least 10°F above the incoming cold-water temperature.
- 03.
Test at every "long-run" fixture (any fixture more than 20 ft of pipe from the water heater).
Documentation
Evidence the inspector / Institute will need.
- 01.
Completed hot-water delivery test record listing each tested fixture with: distance from heater, gallons drawn before delivery, peak temperature reached, time elapsed.
- 02.
Architectural plumbing layout showing hot-water distribution (trunk-and-branch, home-run manifold, or recirculation loop).
Guidance
Why this matters
In a typical home, 10-25% of all hot water drawn never reaches the fixture — it cools in the pipe between uses. A home that passes the 0.6 gal / +10°F test saves 5,000-15,000 gallons of water per year and the energy used to heat it, plus shortens the wait time at the tap (under 10 seconds typical for compliant homes).
Design strategies
Compliance comes from one or more of: (a) home-run manifold distribution with 3/8" PEX trunks, (b) trunk-and-branch with the heater centrally located, (c) on-demand or temperature-modulated recirculation pump at the farthest fixture, (d) point-of-use water heaters for distant fixtures. Insulating hot lines to R-3 helps marginally.
Resources
- PMI Hot Water Delivery System Performance — research
Industry research showing typical hot-water wait times across distribution types.