What is a 'condensing' boiler?

A condensing boiler is designed to take as much heat from the fuel and combustion products as possible and, as a result, is much more efficient. It is also referred to as a high-efficiency boiler (HE Boiler).

Old, traditional boilers usually have a single combustion chamber and expel hot waste gasses through the flue at the top of the boiler at around 180°C making them very inefficient.

Condensing boilers have a larger and more tightly grouped heat exchanger, or in some designs, a second heat exchanger, and gasses are finally released at only around 55°C, wasting far less energy.  They also use less fuel and power and their CO² emissions are much lower than their non-condensing equivalents, which makes them a more environmentally friendly alternative.

All new and replacement boilers fitted after 1st April 2005 must be condensing boilers and have to have a SEDBUK efficiency rating of either A or B.(Exceptions to apply in rare cases).

There are three main types of condensing boilers: combination or better known as ‘combi’s’, system and regular. They all have one thing in common; the ability to extract heat from otherwise wasted flue gasses.

What is SEDBUK?

SEDBUK stands for Seasonal Efficiency of Domestic Boilers in the UK.

The higher the SEDBUK rating your boiler has, the less carbon dioxide you will be emitting into the atmosphere through heating your home or water.

By installing a SEDBUK A-rated boiler, between 90p and 94p of every £1 you spend on power to your boiler is turned into useful heat and hot water.

With a SEDBUK B boiler this reduces to between 86p and 89p out of every £1 and lower for standard efficiency boilers.

Boilers for heating and hot water use much more energy than any other household appliance. For an average household with central heating, 84% of boiler energy consumption is for heating and hot water.

What are the benefits of a High Efficiency A-rated boiler?

Money saving and lower greenhouse gas emissions.

In effect - a permanent discount on gas bills of up to 35%, starting the minute you install a High efficiency boiler.

While you have an initial outlay for your new boiler. within 2 to 3 years your savings will outweigh the cost. Boilers should last around 15 years.

How much could I save?

This will depend on how old and inefficient your existing boiler is.

Old boiler rating Annual saving Carbon dioxide saving per year
G ( < 70%) £300 1,220kg
F (70–74%) £200 810kg
E (74–78%) £150 610kg
D (78–82%) £105 420kg

These are estimated figures based on installing a new A-rated condensing boiler and full set of heating controls in a gas-heated, semi-detached home with three bedrooms.

Source:  Energy Saving Trust

What size boiler do I need?

Our surveyors job is to assess your property and needs to ensure we recommend the right sized for your needs. Getting the right sized replacement boiler is important to ensure the new boiler will run at higher efficiency, with lower running costs and reduced carbon emissions.

Why should I fit controls to my heating system?

Adding controls to your system, whether inbuilt or external, will make your system more efficient and provide you with a consistently comfortable home. To comply with Part L of the Building Regulations you must at least have a simple room thermostat as part of your heating system.

Is it easy to fit a high efficiency boiler?

In most cases it is easy to fit a high efficiency condensing boiler. If it’s your first condensing boiler you will need a new condensation pipe to be fitted by our installers.

Are there restrictions on where boilers can be installed?

Generally boilers can be installed wherever you like. All they require is a flue to the outside and to meet all current building regulations.

How long will it take to conduct my heating survey?

A survey can take between one to one and a half hours depending upon your requirements and the complexity of the installation.  A survey is needed so we can recommend the best type of boiler that suits your individual central heating and hot water needs.

Can you quote the price of a new boiler installation before a site survey?

Unfortunately, no two installations are the same and with gas and building regulations being updated and improved regularly, it’s necessary to conduct an individual survey in order to give you the best advice. There are serveral things that can affect the cost of installation. The most common are:

  • With a new boiler we may have to update your gas pipework and fit thermostatic radiator valves (TRV’s) to abide by current legislation.
  • It is highly recommended to thoroughly flush out the existing central heating system before a new boiler is installed. Failing to install your new boiler onto a clean system would invalidate the manufacture’s warranty as well as affecting efficiency.
  • If you currently have an open vented system with a cylinder and tanks in the loft, this will have to be converted.
Which boilers do you recommend and install?

Our research has led us to recommend and install Vaillant and Worcester Bosch boilers. They are two of UK’s largest and most respected manufactures whose products ensure quality, reliability and value for money.

We provide a 5-year parts and labour guarantee on all new Vaillant or Worcester-Bosch boilers that we install.

We only install products that comply fully with British Safety Standards.

How long does it take to install a new central heating system?

A boiler change can take 1-2 days, an entire central heating system normally 3-4 days.

Will I receive anything in writing when I have a new boiler installed?
Yes, as from 1st April 2005, your local authority must be told when you have a new or replacement boiler fitted. Jon Pritchard will do this for you, and you will receive one of the following certificates:
  • Completion certificates You will receive a 'building regulations compliance' certificate from Gas Safe after the work has been completed. Gas Safe will also advise the local authority that you have had a new or replacement boiler fitted.
  • 'Exceptional circumstances' form If we deem it too difficult or expensive to install a high efficiency condensing boiler in your home, we will give you a copy of the 'exceptional circumstances' form for you to keep.
You should keep these certificates safe as you may need them when you sell your home.
Does the boiler require maintenance?

Your boiler should be serviced annually by a Gas Safe registered engineer. Annual servicing of your heating system and boiler  ensures it is functioning efficiently and can prevent breakdowns.

What is the lifespan of a High Efficiency A-rated boiler?
You can reasonably expect a high efficiency boiler to last from 10 to 15 years depending on usage.
Where can I find out about grants for domestic heating?

Grants are available for a number of energy saving heating systems. To find what is available and if you are eligible visit:

http://www.energysavingtrust.org.uk/proxy/view/full/2019/grantsandofferssearch
What is Carbon Monoxide?

Carbon Monoxide fumes have no colour, taste or smell and can be produced by appliances that use gas, wood, oil or coal. Carbon Monoxide can also be present in smoke from solid fuel or oil appliances. Carbon Monoxide is potentially fatal, and even low-levels of the poison can cause lasting damage to your health.

Have your gas appliances safety-checked annually by a Gas Safe registered engineer

You increase the risk of your appliance producing Carbon Monoxide if it is badly installed or poorly maintained.

If you live in rented accommodation with gas appliances, your landlord must provide you with a certificate from a Gas Safe registered installer to prove the appliances have been safety-checked within the last 12 months