PEX Home-Run Manifold Port and Tubing Takeoff
PEX home-run manifold ports and tubing for one line per fixture.
Example
You enter
- Total fixtures 8
- Fixtures needing hot 6
- Average home-run length (ft) 35
- Waste allowance (%) 10
You get
- Manifold ports 14
- PEX tubing 539 LF
No published worked example is on file for this calculation. It is checked against a hand-worked derivation of its method and an independent reference test.
Details, formula, and sources
Scopecold ports = fixtures; hot ports = hot fixtures; tubing = (cold + hot) x average run x (1 + waste). 8 fixtures with 6 hot needs a 14-port manifold and about 539 LF of PEX at a 35 ft average run; a 12-fixture house (10 hot) needs 22 ports and 847 LF. The manifold is sized to the total ports plus spares; the fixture count drives both. A port count and footage distinct from the flow-sizing pipe-sizing.
Formula or tablecold_ports = fixtures; hot_ports = hot_fixtures; total_ports = cold_ports + hot_ports; tubing_lf = ceil(total_ports x avg_run_ft x (100 + waste_pct) / 100).
Source and editionPEX home-run takeoff identity by name (one port per fixture line; tubing over the average run with waste); first-principles count arithmetic.
Free accessThe count arithmetic is public first-principles; the fixture layout and average run come from the rough-in plan.
What governsEstimate. AHJ and licensed professional govern.
API field namesfixtures, hot_fixtures, avg_run_ft, waste_pct, total_ports, tubing_lf
- Ports one cold port per fixture and one hot port per hot fixture, plus spares at the manifoldhome-run practice
- Average run the average manifold-to-fixture home-run length from the planrough-in layout