New Boiler Cost: What Should You Expect to Pay?

How much does a new boiler cost?

A new boiler cost of about £3,700 is the typical figure the Energy Saving Trust gives for a straightforward gas boiler replacement. That figure includes thermostatic radiator valves.

For a straightforward oil boiler replacement, the Energy Saving Trust gives a typical figure of about £5,500, again including thermostatic radiator valves. The gap between the two is large, so if you heat with oil, budget from the oil figure rather than the gas one.

The Energy Saving Trust is clear that costs vary. A flat with a simple swap and a large house with pipework to change will not land in the same place. Your own new boiler cost could sit well above or below the typical figure.

It helps to know why a new boiler cost moves. The type of boiler, the size of your home and how much needs altering all play a part. That is why quotes for the same house can differ.

Think of the typical figure as a marker rather than a promise. If a quote comes in far above it, ask the installer what is driving the price, and compare that line by line with the other quotes you have. If it comes in far below, ask what has been left out.

Which type of boiler affects the new boiler cost?

The type you choose shapes the new boiler cost, because each type suits a different home. Three kinds are sold for homes in the UK: combi, system and heat only boilers.

Combi boilers do not use a hot water cylinder, so they need less space and there is less to install. They give heat and hot water on demand, which suits smaller households, but they may be less suitable for homes with several bathrooms or low water pressure.

System boilers have a separate cylinder that stores hot water. That suits larger families with higher hot water needs, because you can draw from the tank at several taps at once. Heat is lost from the cylinder over time, though, which is why the Energy Saving Trust says a cylinder should be fully insulated. It says topping up an old cylinder’s insulation to 80mm could save around £35 a year.

Heat only boilers, also called regular or conventional boilers, have two extra header tanks, usually in the loft. They tend to suit larger properties or homes with low water pressure, and are unlikely to suit a flat.

One point worth a thought before you pick. A heat pump can heat water stored in a hot water cylinder, so if you switch to a combi now and take the cylinder out, you may need to put one back in if you want a heat pump later.

What should you check before you get a new boiler?

Quotes are where a new boiler cost becomes real, so get three. The Energy Saving Trust says it is worth getting three quotes from different installers to make sure you get the best value for money.

For a gas or LPG boiler, the installer must be Gas Safe registered. For an oil boiler, the Energy Saving Trust recommends an OFTEC registered installer. It says a registered installer should confirm the system meets building regulations and give you the paperwork to prove it. Keep those documents safe, because you will need them when you sell the home.

• Ask each installer to quote for the same boiler type, so each new boiler cost compares fairly.
• Ask what is included, for example controls, radiator valves and removing the old boiler.
• Check the installer’s registration: Gas Safe for gas and LPG, OFTEC for oil.
• Ask for the paperwork once the job is done and file it with your house documents.

It is also worth asking how the new boiler will be covered after fitting. Our guides to whether boiler cover is worth it and to older boiler cover and age limits explain what cover can and cannot do.

Is a boiler the only option when your old one fails?

No. The Energy Saving Trust expects more and more existing homes to switch to a low carbon heating system such as a heat pump, and a boiler replacement is a sensible moment to think about it.

On its air source heat pump page, the Energy Saving Trust says heat pumps are more than three times more efficient than a gas or oil boiler. It also says that on a standard electricity tariff a heat pump can cost slightly more to run than a new gas or oil boiler, and that on a heat pump time of use tariff it can cost less. So efficiency and running cost are not the same question, and the tariff you are on decides the second one.

A heat pump will not suit every home, and it comes with its own costs. Our guides to what a heat pump costs and the heat pump grant cover that side, and the grant rules are best checked on the scheme’s own pages.

Whichever way you go, your new boiler cost is only part of the bigger bill. Heating and hot water account for over half of what you spend in a year on energy bills, according to the Energy Saving Trust, so it is worth checking your gas and electricity deal while you are at it.

Compare energy deals

Frequently asked questions about new boiler cost

Sources

• Energy Saving Trust: Boilers, last updated 3 January 2024. Source of the £3,700 gas and £5,500 oil replacement figures (the page does not say which areas they apply to), the three quotes advice, the Gas Safe and OFTEC registration points, the building regulations paperwork, the £35 cylinder insulation saving and the statement that heating and hot water account for over half of annual energy spend.
• Energy Saving Trust: Air source heat pumps, last updated 20 October 2026. Source of the more than three times more efficient figure and the running cost comparison on standard and time of use tariffs.

Checked 10 November 2026.