Hydronic Pipe Sizing Calculator
Size copper and steel pipe for hot water heating from BTU load per ASHRAE Fundamentals Ch. 22 and Bell & Gossett methodology
Free hydronic pipe planning calculator for HVAC contractors, mechanical engineers, and plumbing designers. Enter the heating or cooling load in BTU/hr and the design temperature differential to screen required GPM, local straight-pipe friction, and velocity for Copper Type L, Copper Type M, and Black Steel Schedule 40. The app includes ASHRAE, ASTM, CDA, Dow, and Bell & Gossett source pointers, but the local pipe rows, C factors, glycol properties, and limits remain planning data that need current source, manufacturer, project, and qualified review.
Check expansion-tank assumptions for the same loop
Expansion Tank Sizing Calculator →Calculate glycol performance penalties
Glycol Freeze Protection Calculator →Check pipe pressure drop for existing piping
Pipe Pressure Drop Calculator →Check pump affinity-law prompts before curve review
Pump Affinity Laws Calculator →How It Works
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Enter the Heat Load
Enter the BTU/hr load from a current load calculation, equipment schedule, or measured project basis. For multi-zone screens, add zones individually to compare branch and header assumptions.
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Set Screening Parameters
Choose design ΔT, pipe material, fluid type, local straight-pipe friction limit, and velocity limit. Treat the defaults as editable planning limits, not a code table or manufacturer rule.
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Review Source Gaps
Use the pipe comparison table as a first-pass straight-pipe calculator. Final design still needs equivalent length, fittings, valves, equipment drops, pump curves, glycol viscosity, material compatibility, code/AHJ, and qualified review.
Built For
- HVAC contractors documenting preliminary copper-pipe assumptions for residential baseboard loops
- Mechanical engineers checking early commercial hydronic branch and header flow screens
- Plumbing designers comparing local straight-pipe rows before a full pressure-drop model
- Service technicians comparing existing pipe sizes against updated load assumptions during renovations
- Solar thermal installers flagging glycol-flow caveats before product and pump review
References
- ASHRAE Handbook Fundamentals source pointer for pipe and tube design context
- Xylem / Bell & Gossett System Syzer hydronic design manual source pointer
- ASTM B88 and Copper Development Association source pointers for copper tube context
- ASTM A53/A106 source pointers for steel pipe context
- Dow product-page source pointers for glycol heat-transfer fluids