Condensing Boilers

Condensing boilers are the most energy efficient boiler which can be installed. A saving up to £230 can be made each year, but the initial cost is much higher than a standard boiler.

New building regulations introduced in April 2005 state that any new boilers installed must be condensing.

There are two different types of condensing boilers available:

  • System or regular - This will work with your existing hot water cylinder. It is the best choice if you have more than 2 bathrooms or your mains pressure is low.
  • Combi - The original tanks can be removed and the combi boiler will produce hot water on demand.

How do condensing type boilers work?

On a standard boiler heat is lost through a flue, on condensing boilers a second or larger heat exchanger is used to trap heat which is normally lost and turns it back into a liquid water or condensate.

Condensing boilers also has a gas valve which can regulate the temperature, this means that if the house is up to the temperature required rather than turning on and off like a standard boiler it will turn the gas down and therefore reduces the temperature and save money.

How do I know if a condensing boilers are energy efficient?

All appliances come with an energy rating; the most efficient boilers will have a rating of either A or B. Check with the installer how efficient the boiler is.

Check with your installer for recommendations and the size of the boiler required. All work carried out on any gas appliances must be done by a registered CORGI (Council of Registered Gas Installers) engineer.

Are there any grants available for installing condensing boilers?

There are government grants available under the warm front scheme, have a look to see if you qualify. Grants are available up to 2700 for gas and 4000 for oil. The warm front grant can be used for insulating and heating improvements made to your home.

The Government has also introduced a scrapage scheme for old boilers rated 'G'. The scrapage is worth 400 if you pruchase an 'A' rated boiler. The scrapage is open for householders and landlords who own property. You need to apply for a voucher, which is valid for 12 weeks from date of issue. To apply for a voucher you will need to speak to your registered installer to see if your boiler is eligable and then complete a email to the Energy Saving Trust scheme.

Getting quotes for condensing boilers

If you are planning to install a condensing boiler it is worth getting at least 3 quotes. Ensure that you request the type of boiler you require, some installers will only recommend combi boilers. If you are planning to install solar water in the future it may be better to install a system boiler.

A few things to enquire about:

  • The gas pipes on old boilers are more narrow than new condensing boilers.
  • The flue from the old boiler is far enough from an opening window.
  • A pipe needs to be connected from the boiler to a drain, if possible get it connected inside the house e.g. sink. This will save any freezing in winter.
  • Enquire about timer controls. Some of the new controls allow separate times for hot water and heating. For most people the water is needed for less time.
  • Warranty - Most Condensing boilers come with a 2 or 5 year warranty. If they are a an accredited installer, this may be extended.
  • Ensure that they are registered to complete the work.
  • It may be worth fitting radiator control valves on some of the radiators to control the heat in different rooms.
  • When fitting a new condensing boiler ensure that the system is pressure flushed, this will ensure that the new system will run at its most efficient and without a pressure flush the warranty may be void.

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Did you know?

10 year old boilers could be costing you up to 30% more on fuel

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