Introduction
One of the most common questions when specifying an underfloor heating system is: how many ports do I need on my manifold? Get it right, and your system will run efficiently and evenly. Get it wrong, and you could face uneven heating, pressure issues, or costly modifications down the line.
In this guide, we'll walk you through exactly how to calculate the number of ports you need — and why it matters.
What Is a Manifold and What Do Ports Do?
A manifold is the central hub of a wet underfloor heating system. It distributes hot water from your boiler or heat pump to individual heating loops across your floor. Each port on the manifold connects to one loop of pipe — one zone of heating.
So the number of ports you need is directly tied to the number of heating loops (zones) in your system.
How to Calculate the Number of Loops You Need
Each heating loop typically covers a maximum of 100–120 metres of pipe. The spacing of your pipe (usually 100mm–200mm centres) and the area of each room will determine how many loops are needed per room.
As a general guide:
- Small rooms (up to 10m²) — typically 1 loop
- Medium rooms (10–20m²) — typically 1–2 loops
- Large open-plan areas (20m²+) — may require 3 or more loops
For example, a 4-bedroom house with a kitchen, living room, and 2 bathrooms might require 8–12 loops in total — meaning you'd need an 8 to 12 port manifold.
Common Manifold Port Configurations
Manifolds are typically available in the following port configurations:
- 2 port
- 4 port
- 6 port
- 8 port
- 10 port
- 12 port
It's always worth choosing a manifold with one or two spare ports if your layout permits — this gives you flexibility to extend the system in the future without replacing the manifold.
Single Manifold vs Multiple Manifolds
For larger properties or multi-storey buildings, it's common to install multiple manifolds — one per floor or per zone. This keeps pipe runs shorter and the system easier to balance and maintain.
Each manifold should be positioned as centrally as possible to the loops it serves, typically in an airing cupboard, utility room, or purpose-built manifold cabinet.
Key Takeaway
The number of ports you need equals the number of heating loops in your system. Calculate your loops based on room size, pipe spacing, and maximum loop length — then choose a manifold that matches, ideally with a port or two to spare.
If you're unsure about your design, our range of manifolds covers 2 to 12 ports, and our team is on hand to help you specify the right solution for your project.