Heat Networks in Flats and Apartments: Benefits, Costs and What You Can't Control

What Is a Heat Network?

A heat network (also known as district heating or communal heating) distributes heat — typically in the form of hot water — from a central energy source through insulated pipes to multiple buildings or dwellings. Rather than each home having its own boiler, residents connect to the network through a Heat Interface Unit (HIU), which transfers heat from the network into the home's heating and hot water system.

In the UK, heat networks supply approximately 480,000 homes, predominantly in urban areas, high-density new-build developments, and social housing estates. The proportion of new flats connected to heat networks has grown significantly as housebuilders respond to planning requirements and the push toward low-carbon heating.

How Heat Networks Work in Practice

The central energy source for a heat network can be a gas combined heat and power (CHP) plant, a communal heat pump, waste heat recovered from industrial or data centre processes, or energy from waste (EfW) facilities. The heat source significantly affects both the carbon intensity and the running costs of the network.

Each connected dwelling has a HIU — a box typically installed in a cupboard — that allows the building management to meter heat consumption per flat and provides the heat exchanger between the network and the individual home. Smart meters on HIUs enable accurate billing by consumption, though some older networks still charge a flat rate or estimate based on property size.

The Consumer Perspective: What You Control and What You Don't

This is the central issue for residents on heat networks. Unlike a household with its own boiler, a heat network resident:

• **Cannot choose their energy supplier:** You are locked into the network operator's tariff, which is set by the building owner, housing association, or private company running the network.
• **Cannot shop around for a better tariff:** Unlike electricity and gas, where you can switch supplier freely, heat network contracts are tied to the property.
• **May have limited transparency on tariff setting:** Until recent regulation, network operators were not required to disclose how they calculated tariffs or to offer any benchmarking against market rates.

This captive consumer position has led to documented cases of excessive tariff increases, poor service response to breakdowns, and billing disputes without adequate resolution pathways.

Ofgem Regulation: The 2025 Change

Following the Heat Networks (Consumer Protection) Act 2023 and subsequent secondary legislation, Ofgem became the regulator of heat networks in Great Britain from January 2025. This is a landmark change.

Under Ofgem's regime, heat network operators must:

• Register with Ofgem and comply with authorisation conditions
• Meet minimum standards for reliability, billing accuracy, and complaint handling
• Provide access to a redress scheme (parallel to the Energy Ombudsman for gas and electricity)
• Publish information on tariff benchmarking and billing methodology
• Meet efficiency standards for network operation

The regulations are being phased in, with full consumer protection standards expected to be effective across all networks by 2026. Smaller networks (below 500kW heat output) face a later compliance timeline.

Tariff Structure and What You Should Expect to Pay

Heat network tariffs typically consist of two elements:

**Standing charge:** A fixed daily or monthly charge covering the cost of maintaining the network, HIU, and metering infrastructure. This is often significant — £300–£700/year is not uncommon for large urban developments.

**Unit rate (p/kWh):** The cost per unit of heat consumed. This should ideally be comparable to gas heating costs (gas is approximately 5–7p/kWh at current tariff rates). However, many heat network unit rates are higher — 8–15p/kWh is frequently reported — particularly where networks are less efficient or use more expensive energy sources.

The combined cost of standing charge and unit rate should be comparable to or lower than the equivalent cost of individual gas heating for the consumer to be receiving fair value. Ofgem's benchmarking work should make this comparison clearer for consumers in due course.

What to Check When Buying a Flat on a Heat Network

If you are purchasing a leasehold flat connected to a heat network, ask:

• Who operates the heat network, and what is the current tariff?
• What is the standing charge?
• What fuel source does the network use, and what are the planned changes?
• Has there been any indication of significant tariff increases in recent years?
• Is the HIU under a maintenance contract, and who pays for HIU repair or replacement?
• What is the process for reporting a heating failure?

Property Passport UK displays EPC data for flats including the energy efficiency and environmental impact ratings, which can give a useful indication of the typical energy costs in a development even before the specific network tariff is known.