Combi Boiler Price & Cost Guide

Whether you’re replacing an old boiler or installing a brand new one, a combination (combi) boiler will keep your home warm and energy efficient.

What is a combi boiler?

There are two types of boilers:

1. Regular system boilers – these have a separate cylinder to store hot water in. System boilers are good for households with extensive hot water needs.
2. Combi boilers – have no cylinder and heat water on demand instead. They are more efficient overall, says the Energy Saving Trust (EST), because no heat is lost through the cylinder.

How much does a new combi boiler cost?

The cost of a combi boiler will vary depending on size, make and what type of fuel it burns. The EST reports that the average price of a new gas boiler is around £2,300, including installation. Here are some more specific prices for gas combi boilers:

• The Alpha CDC combi boiler which is EST recommended (meaning it’s at least 90% efficient) costs from £504.32 excluding VAT from Discounted Heating online
• A Baxi combi boiler direct from the manufacturer costs £650 to £900
• A Vaillant combi boiler from the manufacturer costs £725 to £910
• A Worcester Bosch combi boiler from the manufacturer costs £730 to £1,010

Get more information on new combi boiler prices.

Oil combi boiler prices

Oil combi boilers usually cost slightly more to buy and run but are a good option if you don’t live on the gas mains. Example prices are as follows:

• A Therma Saver oil combi boiler from Discounted Heating online costs £1,434 excluding VAT
• A Greenstar Camray oil combi boiler from Discounted Heating online costs £1,038.10 excluding VAT
• Warmflow quote their standard oil-fired combi boilers to cost between £1,700 and £1,950

Get more information on oil combi boiler prices here.

Cheapest combi boiler prices

You may be able to find a cheaper combi boiler if you buy a second hand or reconditioned model. For example:

• A recently reconditioned combi boiler can cost between £600 and £900
• Ex-showroom combi boilers can cost between £450 and £750

Get more information on the cheapest combi boiler prices.

Combi boiler installation costs

On top of the cost of your new combi boiler, you will need to pay for it to be professionally installed by:

• A Gas Safe engineer when installing a gas combi boiler. It’s a legal requirement in the UK that anyone who installs, services or repairs gas appliances must be registered with Gas Safe
• A member of the Oil Firing Technical Association (OFTEC) for an oil burning boiler
• A qualified electrician to install an electric combi boiler to BS 7671: 2008 Requirements for Electrical Installation

The EST recommends getting at least three quotes and asking for references before hiring a contractor. If your boiler installer isn’t registered with any of these associations you’ll need to self certify that the installation meets building regulations, which involves paying for a building inspector to check the installation.

Combi boiler installation costs will vary depending on what area of the country you live in, Which? estimate that the installation costs for a new boiler are:

• Around £600 for a replacing an old model with a new one
• Between £1,500 and £1,800 for installing a new combi boiler in a different location

Get more information on combi boiler installation prices.

Combi boiler fitting costs

The cost of fitting your combi boiler will vary depending on who you hire to do the work. The following companies provide combi boiler fitting:

• British Gas charge between £750 and £1,500
• EDF Energy will fit a combi boiler for £750 to £1,350

Get more information about combi boiler fitting costs.

Vaillant combi boiler prices

Vaillant is one of the most well known boiler manufacturers and have been in operation for more than 135 years. This makes the Vaillant combi boiler a popular option; prices will vary depending on where you buy yours from and how big it is:

• A Vaillant Eco-Tec Pro 24 combi boiler costs £610
• A Vaillant Eco-Tec Plus 31 costs  £1,000

Get more information about Vaillant combi boiler prices.

Combi boiler servicing costs

It’s essential that you get your combi boiler serviced at least once a year to ensure that it’s operating safely and efficiently. A service will:

• Detect any serious faults – saving you  money on future repairs and expensive emergency call-outs
• Save your life – by detecting lethal Carbon Monoxide leaks and other dangerous defects
• Reduce your fuel bills – by making sure your boiler runs at its most efficient
• Stop you breaking the law – landlords are legally obliged to carry out annual boiler serviced in rental properties

The EST say that a boiler service will cost between £50 and £75 – find out more about servicing your boiler.

Should I install a combi boiler?

Combi boilers are suitable for:

• Homes with modest hot water needs such as flats or one-bathroom houses. This is because combi boilers struggle to provide hot water to more than one outlet at once
• Small properties – because of their compact size, combi boilers can fit neatly in cupboards or under the stairs and there’s no hot water cylinder to accommodate

Combi boiler regulations

It’s important to comply with the following regulations when installing or replacing a combi boiler:

• Condensing models – as of the 1^st of April 2005, part L of UK building regulations state that all new boilers must be condensing models. This means that they recover more heat from waste gases than non-condensing models and are therefore up to 12% more efficient, says the EST. There are some very rare exceptions to this rule, for instance if the boiler cannot be positioned safely, even when using an extended flue. In these instances a qualified engineer will provide you with a certificate to prove that you need to install a non-condensing boiler instead
• Planning permission – you won’t need planning permission to install your new combi boiler if all the work involved is internal. However, if your new boiler installation involves inserting a flue outside your home, or if you live in a listed building, you should consult your local building authority for advice before installing your combi boiler
• Building regulations - from October 2010, building regulations stipulate that all new boilers should be A-rated or at least 88% efficient according to the Seasonal Efficiency of Domestic Boilers in the UK (SEDBUK) scale. SEDBUK has two rating systems, the 2005 one uses an A-G ranking (A being the most efficient rating) and the 2009 scale works in percentages. The EST say that a new A-rated condensing boiler can save you up to £300 and 1,220kg of C02 per year, depending on what type of boiler you’re replacing
• Heating controls – Part L of building regulations requires you to fit proper heating control systems when installing a new boiler. There are different types of controls to choose from but you basically need a programmable room thermostat to control the timing and temperature of your heating. Good controls can save £55 and 280kg of CO2 per year, reports the EST

Combi boiler grants

You may be eligible for a grant towards the cost of installing or maintaining your combi boiler from one of the following outlets:

The Warm Front Scheme – this is a government scheme for residents in England which is set to be phased out over the next few years. If you own your own home or privately rent, you could be eligible for a grant of up to £3,500 towards heating and insulating your home. A similar scheme called the Warm Homes Scheme runs for those living in Northern Ireland and in Wales you can get help from the Fuel Poverty Scheme.

The Scottish boiler scrappage scheme – the Scottish government have extended their boiler scrappage scheme whereby they offer £400 per household towards the cost of replacing an old (typically one over 10 years old) with a new Energy Saving Recommended boiler. Terms and conditions apply; consult the EST to find out if you’re eligible. Elderly Scottish residents and those on benefits may also be able to get a grant through a local government Energy Assistance Package.

Energy supplier grants – Carbon Emission Reduction Targets (CERT) require energy companies to help their customers make energy saving home improvements. This may include providing discounts for new boiler installation. You’re eligible for grants from any energy company, not just the one who supplies energy to your home.

Local government grants – your local government or home improvement agency (HIA) may also provide grants towards the cost of heating and insulating your home – ask yours for more details.

*Sources: Energy Saving Trust, Discounted Heating online, Baxi, Valliant, Worcester Bosch, Warmflow, Gas Safe, OFTEC, Which?, British Gas, EDF. All information is accurate as of January 2012