Understanding Heat Networks

This chapter demystifies how heat networks work, what components matter most, and why understanding the basics helps with efficient, compliant management.

What is a Heat Network?

A centralised system supplying unlimited heating, cooling and hot water to multiple homes or buildings through insulated pipes 24/7/365.
Defined by regulations: "if heat is transferred by water, steam or chilled liquids to more than one end user, it's a heat network."
Types:
- District Heat Network – serves two or more buildings.
- Communal Heat Network – serves a single building with multiple users.

How Does it Work?

Heat (or cooling) is generated in a central location, known as an Energy Centre.
Heat travels via a primary circuit (distribution pipes).
At each apartment, a Heat Interface Unit (HIU) delivers heating and hot water via the secondary circuit.
Meters track usage for fair billing.

Components of a Heat Network

Heat Networks - The Basics

This example shows a standard communal heat network powered by gas boilers. There are many variations, but this is the simplest way to explain the principle.

On the right, you can see the primary circuit at building level.
Gas enters through the main gas meter and fuels the boilers in the energy centre, where heat is generated.
All the equipment in this energy centre is a major capital asset - and it will need ongoing service and maintenance to perform properly.

The Main Network - Primary Circuit

Heat leaves the energy centre and is pumped as water around the building through a network of pipes.
This is where most heat loss occurs. Corridors and communal spaces can often become overheated as a result.
Heat loss is unavoidable, but the level of loss is a key performance indicator and can be managed with the right maintenance and insulation.

In the Apartments - Secondary Circuit

Each flat has a Heat Interface Unit (HIU).
The HIU transfers heat from the primary circuit into the apartment's secondary circuit.
A heat meter inside the HIU measures exactly how much heat (in kWh) is used in that apartment.
The resident can then use that heat for space heating (radiators or underfloor) or hot water at the taps.

Why This Matters for PMs

If you manage the building, you're typically responsible for the primary network.
That means you need to deal with performance, losses and fair billing.
The heat network is a major asset – getting the most from it requires proactive maintenance, monitoring and budgeting.
Performance is trackable now in ways it never used to be – and we'll show later how tools and data can make this much easier.

Why Heat Networks Matter

Potential low-carbon solution, supporting the UK's net zero targets.
Reliable supply of heat and hot water 24/7.
Can integrate modern technologies like CHP, heat pumps, and renewables.

Did you know…

Distribution is usually where most heat loss occurs.

Heat networks aren't just pipes and boilers – they're living systems that need to perform. If you don't track efficiency and losses, you'll see costs go up and complaints rise. The good news is performance can be measured, benchmarked and improved very easily.

Want to go deeper?

Check out some further reading: HIU Comparisons and Choosing the Right Control Strategy

Heat Interface Units (HIUs) are the bridge between your network and residents' homes. Get the choice wrong - or use the wrong control logic - and you risk inefficiency, high bills and complaints. This article by d-Analysed breaks it down in plain English:

Direct vs indirect HIUs - what's the difference
Control strategies (P, PI, PID, demand-based) explained
What to prioritise in selection and integration

Quick Poll

Which aspect of HIU systems do you find most challenging?

Understanding direct vs indirect systems
Implementing control strategies
Selection and integration priorities