Gas central heating

 Around three quarters of homes in the UK have mains gas central heating. It's currently the most viable and cost-effective option for many homes but is responsible for a large part of your carbon footprint.

Gas central heating is a 'wet system', which means a gas-fired boiler heats water to provide central heating through radiators and hot water from your taps.

If you need to replace your current gas boiler, it's worth making sure that your new system is as efficient as possible. Plus it's a good time to improve the energy efficiency of your home to help keep it cosy and your bills in check.

If you're not connected to the gas grid, the following are also 'wet systems' which work in a similar way, but burn a different fuel:

• oil central heating
• LPG central heating

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

How much does gas central heating cost?

If you're installing a new gas heating system, factor-in both the costs of installing it and gas use to heat your home. If you're replacing your boiler, you'll already have radiators and pipework, though some may need upgrading.

Installing a gas boiler

A new gas boiler can cost between £400 and several thousand pounds, depending on the type, brand and size. 

Plus you'll need to pay for installation and any extras such as a system clean. If pipework needs changing, or you're moving the location of your boiler it will add to the cost. 

Find out how much a new boiler costs so you don't overpay.

Gas central heating running costs

Gas is around a quarter of the price of electricity per unit (or kilowatt hour). However wholesale gas prices are increasing so it's likely to cost you more over the coming year.

For an average home, it can cost around £500 per year for gas heating and hot water.*

That's a rough guide. Your actual heating bill will be affected by:

• the size of your home
• how well it's insulated
• the efficiency of your gas boiler (see the most energy efficient boilers)
• how much heating and hot water your home uses
• where you live in the UK.

Boiler efficiency is particularly important. Replacing an old G-rated gas boiler with a modern A-rated boiler with a full set of heating controls could save you between £45 and £300 per year (according to the Energy Saving Trust).

*(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) from Ofgem, and the price per kWh for gas according to the price cap, calculated by Which? in October 2021.)

If you're worried about your gas bills, use Which? Switch to compare gas prices and check our 10 ways to save on energy bills.

Will gas central heating be banned?

From 2025 there will be a ban on installing gas boilers in new build homes. 

There are no plans yet to ban replacement gas boilers in existing homes. The government has said that it plans to phase- out the installation of gas boilers beyond 2035. But it will respect consumer choice so no one will have to rip out their existing boiler before the end of its life.

But to reach net zero in the UK by 2050, we'll have to cut gas use. 

Alternative heating systems to consider to future-proof your home include:

• electric heating
• heat pumps
• hydrogen-ready boiler.

Improving your home's insulation is also key to cutting your carbon footprint. Find out more about insulation, including costs and savings.

Is gas central heating bad for the environment?

Gas is a fossil fuel. When your boiler burns gas to heat your home and water it produces carbon dioxide, a greenhouse gas, and nitrogen dioxide. 

Heating is responsible for almost a third of the UK's greenhouse gas emissions, according to the Committee on Climate Change.

Some energy suppliers sell green gas. This is produced when organic materials are broken down, or from landfill gas. 

It releases the same emissions when burnt but can be considered carbon neutral because it doesn't add more CO2 to the atmosphere overall (as it's made from organic materials that absorbed carbon dioxide as they grew).

Find out more about green gas.

Pros and cons of gas central heating

Pros

• Modern condensing boilers are very efficient (92% or more since 2018)
• Replacing an old gas boiler with a more efficient modern condensing boiler is quite straightforward
• Gas is a relatively cheap way to heat your home and the most viable option for most at present

If your boiler breaks, or you need it serviced, use Which? Trusted Traders to find a trustworthy, local heating engineer or use the tool below. Heating engineers must be on the Gas Safe Register.

Cons

• Gas is a fossil fuel, which produces carbon dioxide when it’s burned, contributing to climate change
• Gas prices can fluctuate, impacted by global supply and demand
• If you don't already have gas central heating, it can be expensive and disruptive to install. You'll also need to connect your property to the gas network
• Gas boilers should be serviced every year. Find out how to get the best boiler service.