HVAC Hydronic Pipe Sizing Calculator is the professional tool for HVAC technicians, plumbers, and hydronic system installers. Calculate correct hydronic pipe size based on flow rate (GPM) with automatic velocity and pressure drop calculations — using Darcy-Weisbach hydraulic analysis for accurate heating and cooling system design.
PIPE MATERIAL TYPES:
Copper Type L — Standard copper tubing for residential systems
Copper Type M — Thinner copper for high-pressure applications
Steel Schedule 40 — Carbon steel pipe for industrial systems
CPVC — Plastic pipe for low-temperature applications
PEX — Cross-linked polyethylene for modern systems
CORE SIZING FEATURES:
Flow Rate Sizing — Enter GPM to get recommended standard pipe sizes instantly
Velocity Check — Ensures flow stays within safe limits (optimal 3-10 FPS)
Pressure Drop Analysis — Darcy-Weisbach calculation per 100 ft of pipe
Reynolds Number — Full hydraulic analysis for precision system design
Standard Sizing — All results snap to industry-standard nominal pipe sizes
Instant Results — Calculated velocity and friction loss displayed immediately
FLUID SUPPORT:
Water Only — Standard hydronic heating water calculations
30% Glycol Mixture — Anti-freeze protection for cold climates
50% Glycol Mixture — Maximum freeze protection systems
Automatic Density/Viscosity — Adjusts calculations for fluid type
ADVANCED CALCULATIONS:
Pressure Drop Per 100 ft — Complete friction loss analysis
Velocity Verification — Confirms proper flow rates prevent erosion
Temperature Compensation — Fluid property adjustments for climate
Frictional Loss Charts — Professional reference data included
OPTIONAL PRO UPGRADE — $2.99 ONE-TIME IN-APP PURCHASE
The following features require a separate one-time in-app purchase. They are not required to use the calculator:
• Unlimited saved calculation history
• PDF export of results
• Dark theme
• Ad-free experience
WHY HYDRONIC & HVAC PROS USE THIS APP:
Faster pipe sizing than friction loss charts and tables
Accurate sizing prevents undersized/oversized pipes
Reduces pressure drop problems in hydronic systems
Ensures proper flow velocities for system efficiency
Prevents erosion damage in copper piping (>10 FPS)
Prevents noise and cavitation in hydronic systems
PERFECT FOR:
HVAC technicians designing hydronic heating systems
Plumbers sizing water and glycol piping
Hydronic system installers planning equipment layouts
HVAC contractors preparing accurate material estimates
Geothermal heat pump system designers
Radiant floor heating system design
HVAC students learning hydronic calculations
Building commissioning engineers
Based on Darcy-Weisbach friction loss methodology and industry-standard hydraulic calculations.
Part of HVACTools Suite — professional HVAC technician tools for hydronic design, refrigeration diagnostics, and field calculations.