Hydronic Loop Sizing Calculator (Radiant Heat)
What pipe size should a hydronic loop be?
The tool selects the smallest nominal pipe size whose water velocity stays at or below 4 ft/s, the common residential noise-and-erosion ceiling, for the computed flow. Friction loss is then calculated with the Hazen-Williams equation using the C-factor for your chosen material. For radiant loops, a 2–3 ft/s target is preferred to limit air entrainment.
Run the numbers for your project
Use the Hydronic Loop Sizing Calculator (Radiant Heat) to get an exact answer for your inputs.
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