We use cookies to allow us and selected partners to improve your experience and our advertising. By continuing to browse you consent to our use of cookies. You can understand more and change your cookies preferences here.

Home & garden.

Updated: 30 Jun 2021

Gas central heating

Learn more about gas central heating systems and gas boilers, including how much they cost to run per year - so you can find out if you're paying too much.
Sarah Ingrams
Gas hob 451081

Most households in the UK have mains gas central heating. Find out if you're paying too much for gas, and learn more about the pros and cons of gas central heating.

Gas central heating is a so-called ‘wet system’, which means a gas-fired boiler heats water to provide central heating through radiators and hot water through the taps in your home.

Some houses that aren’t connected to the gas network can use electrical heating, liquid petroleum gas (LPG) or heating oil, which work in a similar way to gas central heating. LPG and oil are delivered by road and stored in a tank, which you may have to buy or rent from your supplier.

Annual average cost of gas

The average annual cost for heating and hot water using gas in the UK is £542, based on your home using around 12,000 kWh a year*. 

Remember, this cost is just a guide to help you compare costs of different types of fuel. There are a number of factors that affect energy bills, including the age of your home and insulation, the efficiency of a hot water and heating system, and where you are in the UK.

If you're worried about your energy bills, it's worth seeing whether you're on the right energy tariff for you by using our free energy switching service, Which? Switch to compare gas prices.

Choosing the best gas boiler

Buying an efficient, reliable boiler will give you both peace of mind and lower heating bills.

Compared with an old G-rated gas boiler, you could save £652 per year on heating with a modern A-rated condensing boiler.

But not all boiler brands are equal. Buying a new gas boiler can cost between £500 and £3,000 (not including installation), so it’s a very expensive decision to get wrong.

Find the most reliable boiler brands, as rated by their customers and experienced heating engineers, in our Best Buy boilers.

Pros and cons of gas central heating


  • Modern condensing boilers are very efficient (some more than 90%), so you get a good return on every unit of energy.
  • Replacing a standard gas boiler with a very efficient modern condensing boiler is quite straightforward.
  • You don’t need to store gas, as it’s piped directly to your home.

If your boiler breaks, or you need it serviced, finding a heating engineer on the Gas Safe Register scheme (by law, anyone who works on boilers must be registered) should be fairly easy. Find trustworthy, local heating engineers by visiting Which? Trusted Traders.  


  • Gas is a fossil fuel, which produces carbon dioxide when it’s burned. So it’s not a clean source of energy.
  • The UK isn’t self-sufficient for gas so prices are impacted by demand around the world.
  • Installing a gas central heating system from scratch can be expensive and disruptive. If you’re not on the gas network, connecting your property can also be costly.
  • Gas boilers should be serviced every year to keep them running efficiently and last as long as possible. This can cost around £100. Find the best boiler cover.

If you're looking to gas central heating installed in your home or you need you gas boiler serviced, use our Which? Trusted Traders search tool below. You don't have to be a Which? member to use Which? Trusted Traders.

*(The estimated cost of heating and hot water using gas is calculated using the average annual heat demand for a medium user (12,000 kWh), as calculated by Ofgem, and the price per kWh for gas, calculated by Which? in Oct 2017.)