Why is a condensing boiler greener than a non-condensing one?

Unlike a conventional boiler which wastes some of the heat it produces by releasing waste gases from its flue, a condensing boiler uses some of the heat from these waste gases to heat water returning from your central heating system, so it requires less heat from the burner. This makes a condensing boiler more efficient than a conventional (non-condensing) boiler.

So why does every house not have a condensing boiler?

As yet only a small proportion of houses in the UK have a condensing boiler due to two reasons - lack of awareness and, in the past, higher boiler cost.

As technology progresses, the unit price of a condensing boiler has fallen more in line with a conventional one, particularly taking into account the £200 cash back schemes offered by the Government. Coupled with the lower running costs, the payback period of installing a condensing boiler has shortened significantly.

Developers seeking to maximise their own profits are not concerned with payback times and will install the cheapest conventional (non-condensing) boiler they can get away with. Sadly few buyers will truly consider what they are paying for in the first place. It is often only the self builders who are motivated and interested enough to research the best product for their home.

If you currently have a conventional boiler that it is not efficient, you should consider changing it. Most existing boilers are suitable for being replaced by condensing boilers. They are available as floor standing and wall-hung units, and as regular or combination boilers and are as easy to install as non-condensing boilers.

Extended fluing options are available if required, they can be installed in fully pumped heating systems without the need for any special designs and the only difference in installation is the requirement for a condensate drain.

How do condensing boilers work?

Some new condensing boilers can be up to 92% efficient compared to new non-condensing ones that are around 78% efficient and older boilers that are only 55 to 65% efficient. The higher the efficiency of your boiler the less units of fuel you need to burn to keep your home at the right temperature - better for your wallet and the environment.

Like conventional boilers, a condensing boiler burns fuel to heat the water in a metal heat exchanger. To maximise heat transfer and recover useful heat from flue gases, a condensing boiler uses an extra-large heat exchanger (or sometimes two). When they are functioning in condensing mode the flue gases give up their ‘latent heat' and exit the flue in a visible plume of water vapour at 50-60°C - they're usually 120-180°C in a non-condensing boiler.

How do you get the maximum efficiency out of your condensing boiler?

To encourage the boiler to function at optimum efficiency in condensing mode you should:

1. Ensure that your insulation and window seals are up to scratch

2.. Try to get the water returning to the boiler to be at the right temperature to encourage condensing - around the mid 50s degrees centigrade.

3. Install an outdoor weather thermometer (also known as 'weather compensation') which more accurately predicts the heat that is actually needed.

4. Use larger radiators - the whole heating system can work at lower temperatures (again encouraging condensing).

Once only of interest to a small minority, green is the new black as far as self-building is concerned.

With the effects of global warming becoming increasingly apparent, more and more people are seeking greener ways to provide the energy needed to run a home.

Whether it's solar panels, heat pumps, high specification glazing or eco-friendly wool insulation in the loft space, there is little doubt that it is self-builders who are setting the standards for a greener future for the building industry and the way we live our lives.

Underfloor heating for example, has been available for years but, by and large, the self build market has been the industry's bread and butter - with large scale property developers still opting for standard, less efficient radiators.

But it's not all about saving the planet. Incorporating green ideas into a home can lead to reduced running costs and save you money in the medium to long term too. And when you come to sell your home in the future, you can guarantee that the greener it is the more attractive it will be to prospective buyers.

There is a greater sense of purpose from the government to promote green alternatives too with a stick and carrot approach in place.

Building regulations now demand far better energy efficiency while government grants are available for loft insulation right through to solar panels, heat pumps, wind turbines and other microgeneration technologies.

Self-builders are leading the way as far as greener homes are concerned and greenselfbuild.co.uk will be with you every step of the way towards a greener future for you, your family and the wider community.