Central heating systems

What kind of central heating do you have - and is it the right one for you? From wet systems to warm air, find out more in our guide.

Central heating systems

What kind of central heating do you have - and is it the right one for you? From wet systems to warm air, find out more in our guide..


Keeping our homes feeling warm and welcoming is a huge priority for all of us, but we also want to be able to heat our homes efficiently to reduce the cost of our heating bills.

We rely on our central heating systems and when it’s working properly, we know we can rely on it to work behind the scenes, keeping our homes at a comfortable, even temperature throughout.

But what if your central heating system isn’t working as well as it could be? Is there a different type you could try? Or could you even get free central heating? Find out the answer to all these questions and more in our guide to central heating systems. If you already know what you’re looking for, you can jump straight to that section using the links below:


What is central heating?

Central heating is the process by which heat travels around your home, usually via a system of pipes coming from your boiler, travelling around your home, even under floors, and passing through radiators. This heat can be adjusted using a central heating thermostat, time controller or radiator valves to help you find the perfect temperature at the right time.

Do I have central heating?

Probably, because 95% of the homes in the UK have some form of central heating, according to the Office of National Statistics.

You can say your home is centrally heated if the warmth is generated in one central place (normally a boiler) and then distributed throughout your home via pipes to radiators or underfloor heating. Your boiler may be in the kitchen or in an airing cupboard and will work by burning some kind of fuel - most commonly natural gas provided through the mains supply. If you don’t have central heating, your home could be heated locally, meaning you have separate heating units in each room that work independently of each other.

What type of central heating do I have?

You probably have a gas-powered wet system. In the UK, gas-powered boilers that heat water to distribute warmth are the most common type of heating system – used by around 83% of homes nation-wide.

Natural gas that comes from the mains supply is preferred as it’s not only a cheaper option compared to homes that aren’t connected to the grid who need to rely on more expensive heating options like LPG or heating oil, but also has lower carbon dioxide emissions , with the exception of wood.

Although natural gas from the mains is the most energy efficient and so the cheapest option, according to Which? [1] around 4 million households in the UK are unable to connect to the national gas network at all. In that case, they may have electric storage heaters, or use a different kind of fuel to power their boilers.

What are the different forms of central heating?

There are four main types of central heating available: wet systems, electric storage heaters, warm air systems and district heating. Most common are wet systems, followed by storage heaters. Warm air systems were popular in the seventies but have become less popular, while district heating is only available in certain areas.

How can I tell which central heating system I have?

Wet systems

Wet systems are the most popular kind of central heating in the UK. You can tell if you have a wet system if your boiler burns fuel to heat water which is then pumped into either radiators or underfloor pipes to heat your home.

Advantages:as most wet systems run on a gas boiler, you’re able to heat your home cost effectively, because gas is around three times cheaper than electricity.

Electric storage heaters

Electric storage heaters use radiators filled with bricks that are extremely efficient in storing large amounts of heat. The radiators use off-peak electricity to ‘charge up’ overnight and then release the stored heat during the day when it’s needed.

Although they’re wall-mounted and look like a radiator, it’s easy to tell if your home is heated with electric storage heaters. Your home probably won’t have a boiler and the radiators have both input and output controls, that allow you to regulate how much heat is being stored and emitted.

Advantages: electric storage heaters are much cheaper to install than gas central heating, and require very little servicing.

Warm air systems

Warm air systems were very big in the seventies, and despite their popularity dwindling, you’ll find that some older properties are still heated in this way.

You’ll know if you have a warm air system if instead of water, cold air is sucked in from the outside and then gets heated by the boiler. It’s then taken around the home in ducts and released into rooms through wall vents.

Advantages: heating air is very efficient – it can heat a room quickly, and stop damp and condensation from building up.

District heating

Popular after World War II and typically using natural gas, household waste or biomass, it’s an easy way to heat large housing estates built after the Blitz. Around 220,000 households still benefit from district heating, most notably in areas like Nottingham, Sheffield and Pimlico in London and this form of heating is becoming increasingly more popular for London developments where they must be zero carbon.

You’ll know if you have district heating if you have no boiler, and you get your hot water via a centralised heating source from insulated pipes.

It’s great because it’s super energy efficient but for many people with this sort of heating, they’re not able to take advantage of a competitive switching market, so if you’re moving into a property that might have this sort of heating, it’s worth checking this before.

What are the alternatives to mains gas central heating?

Although natural gas from the mains is the most energy efficient, and therefore cheapest option, around 4 million households in the UK are unable to connect to the national gas network at all.

If you’re unable to connect to the gas grid but still want all the advantages of a ‘wet’ central heating system, you could get a boiler that runs on oil, LPG (liquid petroleum gas), wood or coal.

Oil-fired central heating

According to uSwitch [2] around 1.5 million homes in the UK run their boilers on domestic heating oil. It is more expensive than mains gas, but in rural homes it’s the only option - and can work out significantly cheaper than all the costs associated with gas network connection. Luckily oil is a highly efficient fuel so you get a good return for your money.

Unlike mains gas, the fuel for oil-fired central heating is delivered by road in bulk and stored in a large tank that you’ll either buy or rent from your supplier. It’s up to you to make sure you don’t run out – although some suppliers do now have systems which monitor fuel levels and notify suppliers automatically when stocks are running low.

Wood burner central heating

Otherwise known as a biomass heating system, wood burners use logs or wood chips to provide heat and hot water. As wood is a low-energy-density fuel, you’ll need lots of storage space to make this a feasible option. It is more environmentally friendly, but it’s only a zero-carbon option if you have access to wood – say from a nearby woodland or waste wood source – because otherwise you may need to buy wood that has been transported a considerable distance.

LPG central heating

LPG is an alternative to oil central heating and has lower carbon emissions. In fact, LPG has one of the lowest carbon emissions of any fossil fuel. It’s a mix of hydrocarbon gases that are compressed to form a liquid, meaning you can store more of it in a smaller space. In fact, LPG tanks can be buried so they don’t ruin the look of your garden. Similar to camping gas, it can either be delivered to your tank or it arrives in bottles. It is generally more expensive than heating oil and there are fewer suppliers, making it more difficult to shop around and get a better deal.

Coal-fired central heating

If you have a coal stove, perhaps as a feature in your living room, this can be connected to power your boiler and provide central heating and hot water. As with wood, you’ll need lots of space to store your fuel, and it can be an effort to move the coal and feed the boiler. However, some modern coal fired central heating has a gravity feed option to top it up automatically.

Can I change central heating types?

Theoretically you can change both your central heating system and the kind of fuel it runs on at any time, but if you’re already using a mains gas to run a wet system you’re already heating your home in the most efficient (and therefore cheapest) way possible.

If you’re currently using electric storage heaters, it may make sense to change your central heating to a gas boiler-powered wet system. You’ll pay around £2,300 for a gas boiler, plus the cost of the radiators, but you could slash your heating bills by half, and save by around £560 a year [3].

If you can’t connect to the national gas grid, a great option is to install a wood-burning central heating system. According to the Energy Saving Trust, a wood-fuelled biomass boiler could save you up to £800 a year compared to electric heating.

How does my central heating system work?

Wet central heating

Water is heated by the boiler and pumped through all the radiators in turn, before heading back to the boiler again to be heated. Water flows continuously through the system in one circuit, although, as it’s the same water used again and again, this can lead to problems as your radiators age and corrode.

Electric storage heaters

Storage heaters contain bricks which are particularly efficient at storing heat. Electrical heating elements are embedded in the bricks to heat them, and then the stored heat can be released through the radiator, heating the air above it. Some are fan-assisted, meaning they have fans inside that move the warm air through the heater.

How is central heating controlled?

Most systems have a thermostat that’s either permanently mounted in one spot or wireless, meaning it can be moved from room to room. A thermostat monitors the room temperature and switches the boiler off when it’s hot enough, then turns it back on again if the room temperature drops.

Other central heating controls include timers that turn the boiler on or off at set times, programmers that allow you to adjust temperatures for different days of the week and thermostatic radiator valves (TVRs) that let you take control of different radiators.

Another popular option is a smart thermostat. These work remotely via your mobile or computer, so you can adjust the temperature in your home even when you’re not there.

How much does central heating cost?

If you’ve moved into a house with no central heating at all, you’ll need to pay for a new boiler, radiators, pipework and the cost of labour. Prices will vary considerably – top of the range underfloor heating or fancy ornate radiators are more expensive – but as a rough guide, central heating for an average-sized three-bedroom property should cost around the £4,000 mark [4].

Can I get free central heating?

The government runs an Affordable Warmth scheme, designed to help people who are most in need update their central heating systems so that it works more efficiently. While it may not fund the cost of a brand new central heating system, you may be eligible for a brand-new boiler under npower’s ECO scheme.

There are other government grants that can help with your energy bills or make your home more energy efficient. To see if you’re eligible visit the Energy Grants Calculator for more information.

Which is cheaper, gas or electric central heating?

Although electric storage heaters are cheaper to buy and install, if your house is connected to the national gas grid, a gas-fired central heating system is usually the cheapest option for heating your home.

Electricity is about three times the price of gas per kWh (using standard rates) so, with an efficient modern boiler, gas is one of the cheapest way to heat your home.

What can I do to maintain my central heating system?

To keep your central heating system well-maintained and running in great condition, try the following tips:

Check the radiators regularly for cold patches

If they are colder at the top, your radiators may need bleeding. Cold patches at the bottom may indicate that there’s a build-up of sludge and corrosion that needs to be dealt with professionally.

Check the pressure

The pressure should be between one to two bars. If it’s above or below this, you’ll need to repressurise your central heating system, following the manufacturer’s instructions.

Use your central heating timers

Not only does this save you money by only heating the house when you need it, it will also keep your central heating working properly as a boiler that’s running constantly is more likely to break down.

Check the pilot light

Your pilot light should always be a crisp, blue colour. If it’s yellow or orange, or even has a slight orange tinge, it means the gas-to-air mixture in your boiler is wrong, and that too much air is getting into the system. It could lead to sootiness or smoke, or even the release of deadly carbon monoxide.

Check for breezes around the boiler as that could be the source of the extra air. You could also adjust the screw on the pilot light valve until it turns back to the blue colour. Always read the manufacturer’s instructions first.


[1] Which? – oil central heating
[2] uSwitch - heating
[3] Energy Savings Trust
[4] Homebuilding – retrofit central heating