Types of Central Heating Systems: Which One Suits Your Home?

There are five main types of central heating in UK homes. By far the most common is a wet system, where a gas boiler heats water that is pumped to radiators or underfloor pipes. The others are heat pumps, electric heating, communal heat networks that serve a whole block, and older warm air systems. Which one makes sense for you comes down to whether you have mains gas, how big and well insulated the home is, how much hot water you use, and in a flat, what the building already has.

This guide explains how each type works, how to recognise the one you have, and what each is good and bad at, so you can make a sensible decision when your current system needs repairs or replacing.

Wet systems: a boiler and radiators

In a wet system, a boiler heats water which a pump pushes round a loop of pipes to your radiators and back again. Most run on mains gas. A smaller number use oil or LPG where there is no gas supply, which is rare in London. Since 2005, new gas boilers fitted in England and Wales have had to be condensing models, so any boiler installed since then should be one. Our guide to condensing vs combi boilers explains what that means.

Within a wet system there are three types of boiler. They are not different heating systems, just different ways of supplying hot water:

Boiler type	Hot water	Tanks and cylinder	Typical home
Combi	Heated on demand from the mains	None	Flats and homes with one bathroom
System boiler	Stored in a cylinder	Cylinder, no loft tanks	Homes with two or more bathrooms
Regular (heat-only)	Stored in a cylinder	Cylinder plus loft tanks	Older houses with the original layout

For more on choosing between them, read what is a combi boiler and our comparison of combi vs system boilers.

Good at: quick heat, familiar controls, and parts and engineers are easy to find. Watch out for: sludge building up in radiators and pipes over time, and pressure problems on sealed systems. Any work on the gas side must be done by a Gas Safe registered engineer. If your radiators stay warm when the heating is meant to be off, see our guide to heating that won't turn off.

Radiators or underfloor heating?

Radiators and underfloor pipes are just two ways of getting heat out of the same hot water. Underfloor heating runs at a lower water temperature over a larger area, which gives an even, gentle warmth and suits heat pumps well, but it is slower to respond and much more disruptive to fit into an existing room. Many homes use both, with underfloor heating in a kitchen extension or bathroom and radiators elsewhere. See our underfloor heating service if you are weighing that up.

Heat pumps

A heat pump takes heat from the outside air (air source) or the ground (ground source) and uses electricity to raise it to a useful temperature. In most homes it replaces the boiler in a wet system, so it still feeds radiators or underfloor heating and usually heats a hot water cylinder.

The key difference is temperature. A heat pump is most efficient when it heats water to a lower temperature than a gas boiler normally would. That means some homes need larger radiators, better insulation or both before a heat pump will keep them comfortable. An air source unit also needs outdoor space for the fan unit, and a cylinder needs a cupboard, which can be a problem in smaller London flats.

In England and Wales, the government's Boiler Upgrade Scheme gives a grant of £7,500 towards an air source or ground source heat pump that replaces a fossil fuel system (figure from GOV.UK, checked September 2026). Gas boilers are not covered by that scheme, and the rules change from time to time, so check GOV.UK before you plan the work.

Electric heating

Electric heating is common in flats, especially in blocks without a gas supply. The main types are:

• Storage heaters: charge up overnight on a cheaper off-peak tariff and release the heat during the day. They work best when you are on the right tariff and understand the input and output controls.
• Panel heaters and other direct electric heaters: simple to fit and control room by room, but they use electricity at the normal rate.
• Electric boilers: heat water for a conventional wet system with radiators, without needing gas or a flue.

Hot water in an electrically heated home usually comes from a cylinder with an immersion heater. If that stops working, our guide to an immersion heater not working covers the usual causes.

Good at: no gas, no flue, no annual gas safety check, and low installation cost. Watch out for: running costs, because electricity costs more per unit than gas.

Communal heat networks

Many London blocks, both older council estates and newer developments, are heated by a heat network. A central plant room heats water for the whole building, or even a group of buildings, and it is piped to each flat. Inside the flat you usually have radiators and a heat interface unit (a box on the wall that looks a little like a boiler) or a hot water cylinder, but no boiler of your own.

Repairs to the central plant and the main pipes are normally the responsibility of the building's operator or managing agent. The pipework, radiators and valves inside your flat may be yours or theirs, depending on the lease or tenancy, so check before you book anyone. Since 27 January 2026, Ofgem has regulated heat networks in Great Britain, with rules on fair pricing, billing and consumer protection, so your supplier now has formal obligations to you.

Warm air systems

Some flats and houses built in the 1960s and 1970s have warm air heating. A gas-fired or electric unit, usually in a cupboard, heats air and a fan blows it through ducts to vents in each room. There are no radiators. These systems still work in many homes, but they are old and parts can be difficult to find. When a warm air unit fails, owners often replace the whole system with a wet system or electric heating rather than repair it. A gas warm air unit needs the same Gas Safe checks as any other gas appliance.

Sealed or open-vented: the part people miss

Wet systems also differ in how the heating water is kept topped up and allowed to expand:

• Sealed (pressurised): there is a pressure gauge on or under the boiler, an expansion vessel and a filling loop. Pressure normally sits around 1 to 1.5 bar when cold. Combis and system boilers run sealed. If the pressure keeps falling, see our guide to a boiler losing pressure.
• Open-vented: a small feed-and-expansion tank in the loft keeps the system filled by gravity, usually next to a larger cold water tank. There is no pressure gauge on the boiler. This is the traditional arrangement with a regular boiler.

Knowing which you have saves time when you call an engineer, and it matters when you change boilers. Moving from open-vented to sealed means removing the loft tanks and checking that the old pipework and radiators can take the pressure.

Which system suits your home?

Your situation	Usually the best fit
Flat or small house with gas, one bathroom	Wet system with a combi boiler
House with gas, two or more bathrooms	Wet system with a system boiler and cylinder
Older house, want to keep the existing layout	Regular boiler, or convert to a system boiler
Well insulated home with outdoor space	Heat pump, possibly with a grant
Flat with no gas supply	Electric heating, or whatever the block's heat network provides
Old warm air unit that has failed	Replacement with a wet or electric system

If your current system works and is safe, there is no legal need to change it. The time to think about the type of system is when repairs are becoming frequent or a boiler is near the end of its life. Our guide to how long boilers last helps with that decision, and the boiler installation cost page covers what goes into a replacement.

We work on wet systems with gas boilers, radiators and underfloor heating across London. An engineer visit costs £95 an hour, and the £60 call-out fee is waived on jobs that run over 2 hours.

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