Energy Saving & Advice

The information in this section is based on the Govt's Energy Efficiency Best Practice
programme. The building-related aspects of this programme are managed by BRECSU,
It relates to gas-fired domestic CH boilers only.

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

That makes it important to choose an efficient boiler, and have it installed in a correctly designed system - both for money-saving and for the environment.

The Energy Saving Trust, set up by the Govt to promote energy efficiency, also advises that 'the largest saving in home energy costs is from a more efficient boiler, even ahead of wall insulation.

The efficiency of the central heating boiler is the major factor affecting the energy efficiency of your domestic central heating system.

Boiler efficiency is dictated by many factors, which include its design, boiler and radiator size relative to design heat load, system controls (pumps, programmers, thermostats, TRV's), regular servicing, and so on. Your installer will be able to advise you on all these.

When replacing your older boiler, the greatest efficiency benefits will be obtained from what is called a condensing boiler.

What is a condensing boiler?

Condensing boilers have nothing to do with condensation and sources of damp inside a house ! Which is a little confusing, so these days many people call them High Efficiency or HE boilers.

In any particular heating system a condensing or High Efficiency boiler is always more efficient than a non-condensing boiler.

It achieves this by including a large heat exchanger which extracts more heat from the flue gases. This has the effect of reducing the temperature of the flue gases, typically from 150-200 degrees centigrade for a non-condensing boiler to 50-60 degrees centigrade for a condensing boiler. There is so much heat removed that the water vapour present in the flue gases condenses and the water needs to run to a drain. As the flue gases condense the heat exchanger becomes wet, which makes it more susceptible to corrosion. To avoid this, these boilers have to be made of corrosion resistant materials, making them a little more expensive than lower efficiency non-condensing models. Over a few years this additional costs can be recouped from lower fuel bills.

What are the benefits to me of a HE boiler ?

Just one :

- you will save money - in effect you will get a permanent discount on your gas bills of up to 35%

It will also benefit the environment, (Nox and reduced CO2) and a regularly serviced system with low running costs may be an added feature if you ever sell up and move house.

How much will I save ?

You will always save money by fitting a HE boiler how much depends on :

- how inefficient is the old boiler you are replacing?

- what size house you live in ?

Broadly, if you live in a 1 or 2 bedroom flat, you will save up to £100 a year. If you live in a detached house, you will save up to £200 a year. The bigger you fuel use - the more you save

What's the catch ?

HE boilers have larger heat exchangers made of corrosion-resistant materials. So they cost more than a comparable standard efficiency boiler. However, continuous improvements in design and manufacturing have reduced the gap significantly.

Otherwise they are designed to fit as easily onto an existing system as a new standard efficiency boiler, with no changes to radiators - it is a common myth that you need over-sized radiators to get the improved efficiency, but the benefit is minimal.

Your installer will need to fit a drain for the condensate. This is not harmful - it is a very weak acid, like vinegar, and can be tapped into your existing drainage system easily.

A HE boiler will emit a plume of vapour. All boilers do this in cold conditions, but it is more noticeable with a HE boiler - because it scrubs so much heat from the flue gases, the water vapour they contain drops below the 'dew point' and either stays as condensate in the boiler or emerges as harmless water vapour from the flue.

There is huge difference in flue gas temperature of a HE boiler compared to non-condensing :

No wonder you save so much by having an HE boiler and not heating the whole street !

Pluming is a sign that the boiler is saving you money, and may affect where you choose to locate the flue terminal.

Payback

You will enjoy reduced gas bills the moment you fit a HE boiler.

If you set that against the extra cost of buying the boiler, the savings will outweigh the cost within 2 to 3 years.

This depends on various factors including house size.

But after that the boiler will last for many years and the savings will increase in line with fuel costs.

How will I know when it's saving me money ?

You will see the difference in your gas bills immediately.

When you see the boiler pluming you know it's saving you money.

Why choose Saunier Duval ?

Saunier Duval have invested heavily in research and development and latest engineering technology to produce a suite of High Efficiency and High Performance boilers to meet every different application. Our commitment to engineering excellence is demonstrated in all aspects of our product and after sales service to all our customers ensuring we meet and then exceed guidelines for energy efficiency and environmental considerations. Please explore the rest of this site to see why Saunier Duval is the right choice for high efficiency.

Where can I get more information ?

Saunier Duval is a member of the Central Heating Information Council (CHIC).

The Society of British Gas Industries (SBGI).

Saunier Duval are members of CORGI (The Council for Registered Gas Installers).

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