Your question
What pipe diameter do I take for the heating loop, and will the flow be fine?
Too small a pipe is noisy and starves the heat; too large is wasted money. TermoFlo works out the right diameter for your loop and checks whether the flow velocity and pressure drop are within sensible limits.
Go to the pipe diameter calculatorHow it works — three steps
- 1
What you enter
The loop power in kilowatts, the temperature difference, and the section length.
- 2
What you get
The required inner pipe diameter (rounded to a standard size), the actual flow velocity, the flow regime, and the pressure drop.
- 3
The decision you make
Choose the pipe size and confirm the velocity and pressure are within reasonable limits.
A worked example with real numbers
A 5 kW loop with a 20 °C difference
For a 5 kW loop with a 20 °C temperature difference, the calculation picks an inner diameter of about 10 mm (the required figure is roughly 8.7 mm). The flow velocity comes out at about 0.76 m/s — within comfortable limits — the flow regime is turbulent, and the pressure drop is moderate, so you won't have to fit an oversized pump.