If your flat is on a communal heat network, your heating and hot water come from a central plant serving the whole building, delivered to your home through a heat interface unit (HIU). You don’t have a boiler, you usually pay the network operator rather than a gas supplier, and your usage is often measured by a heat meter.
Most everyday issues come down to understanding the controls, knowing who’s responsible for repairs and spotting when a problem is in your flat rather than the building. Our heat interface unit page explains how we help residents and landlords.
How does communal heating work?
A central energy centre heats water, often using large boilers, heat pumps or combined heat and power. That water is pumped through insulated pipes to each flat. Your HIU transfers heat from the network to your radiators and tap water, and a heat meter records how much you use.
Why are my heating bills different from a gas bill?
Heat network bills usually include:
- A unit charge for the heat you use, measured by your meter
- A standing charge covering the operation and maintenance of the network
Standing charges on heat networks can be higher than on gas, as they cover the central plant and pipework. Bills vary between networks. If your bill looks wrong, check your meter readings and contact the network operator.
How should I set my HIU controls?
Controls vary by manufacturer, but a few general tips help:
- Use the programmer to heat the flat when you need it, rather than leaving it on constantly
- Set the room thermostat to a comfortable level rather than turning it right up
- Use thermostatic radiator valves to turn down rooms you use less
- Don’t set hot water hotter than needed, but keep it at the temperature recommended by the manufacturer
- Keep the HIU accessible and its cupboard clear
Who fixes what?
| Problem | Usually responsible |
|---|---|
| Central plant or network pipes | Network operator or managing agent |
| HIU in your flat | Depends on your lease or tenancy |
| Radiators and pipework in your flat | Usually leaseholder or landlord |
| Heat meter | Often the network operator |
Check your lease, tenancy or heat supply agreement to confirm.
My heating or hot water has stopped: what should I check?
- Ask neighbours whether they’re affected. If so, it’s likely a building-wide issue; contact the network operator or managing agent.
- Check the programmer and thermostat settings.
- Check the secondary heating pressure gauge on the HIU, if it has one.
- Look for error codes on the HIU display and note them.
- If it’s just your flat, arrange for an engineer to check the HIU.
Our heating and hot water repairs team can diagnose problems in your flat.
Are heat networks regulated?
Heat networks in Great Britain have come under formal regulation, with Ofgem taking on a regulatory role for the sector. Metering and billing rules also apply. Check your network operator’s details and Ofgem’s current guidance for your rights as a customer.
Communal heating in South London and Kent
Many newer developments across Lewisham, Woolwich, Peckham and Croydon are built with communal heating. If you’re a landlord letting a flat on a heat network, it’s worth keeping HIU servicing on your maintenance schedule. See our landlord services.
Frequently asked questions
Can I switch to my own boiler?
Usually not without the building owner’s permission, and it may not be practical or allowed under your lease. Speak to the managing agent first.
Do I need a carbon monoxide alarm with communal heating?
The HIU doesn’t burn fuel, but if you have other combustion appliances in the flat, such as a gas hob, a CO alarm is still recommended.
Why is my flat too hot even with the heating off?
Heat from communal pipework in corridors and risers can warm flats. Report persistent overheating to the managing agent, as pipework insulation or system settings may need attention.
Get help with your HIU
If your heating or hot water isn’t working properly, drop us a message and we’ll send an engineer out to take a look.