Hot Water Flow Rate to KW Input

Calculate the required heat input (KW) based on hot water flow rate and desired temperature rise.

Flow Rate (LPM) 10.0

Temperature Rise ΔT (°C) 35

Heat Input Required

24.42

kilowatts (KW)

Formula Reference

KW = (LPM / 60) × ΔT × 4.186

LPM = Flow rate in litres per minute
ΔT = Temperature rise in degrees Celsius
4.186 = Specific heat capacity of water (kJ/kg·K)
60 = Conversion from LPM to LPS

Important: This calculator provides indicative heat input requirements only. Always consult with a qualified heating engineer for your specific installation requirements.