Estimate circulator pump size for hydronic heating, radiant floor heat, boiler loops, domestic hot water recirculation, and closed-loop systems. Calculate required GPM, head loss, BTU load, temperature drop, pump horsepower, pipe velocity, and capacity margin.
GPM from BTU load:
The calculator estimates required flow from heating load and temperature drop.
Head loss:
The calculator estimates head loss from flow, pipe size, loop length, fittings, valves, and pipe material.
Pump horsepower:
The calculator estimates hydraulic horsepower from GPM, head, and pump efficiency.
Capacity check:
The calculator compares known pump flow and head against the estimated system requirement.
A circulator pump size calculator helps estimate the pump duty point needed for a hydronic loop.
It can help compare BTU load, temperature drop, GPM, loop head loss, pipe velocity, pump horsepower, and pump capacity margin.
Your result shows estimated circulator GPM, required head, and pump horsepower. Use this as a planning estimate only. Final circulator selection should be checked with the pump curve, actual pipe layout, valve losses, boiler or heat exchanger pressure drop, glycol concentration, zoning, and manufacturer data.
Estimate the required GPM from the heat load and temperature drop, then estimate the head loss of the longest loop. Choose a circulator that can deliver that GPM at that head.
For a closed hydronic loop, head is mainly the friction resistance through pipe, fittings, valves, boiler, heat exchanger, and other devices. It is not the building height in a closed loop.
A 20°F temperature drop is common for many hydronic heating estimates, but radiant floors, boilers, and specialty systems may use a different design temperature drop.
No. This calculator gives a planning estimate. Final circulator sizing should use the actual system design, component pressure drops, fluid type, and pump curve.