Home How To Cost of high efficiency, condensing boiler and how to buy

Cost of high efficiency, condensing boiler and how to buy


Anyone installing a boiler must be qualified and registered as per the local regulations. In the U.K. they must be on the Gas Safe Register.

Installing this gas appliance is not a suitable task for the home handy-man. In addition to being potentially dangerous, it could invalidate the manufacturers’ warranty and it would be a criminal offence to do so, in some parts of the world.

Replacement Boiler for Existing Heating System

A certain procedure must take place when a new boiler is installed or an existing boiler is moved to a new location in the same property. The procedure is laid out in law (Building Regulations, U.K.). It is standard good practice and it means that your heating system should work at its best.

The whole system must be flushed, cleaned and a corrosion inhibitor must be added;
Any exposed heating or hot water pipes must be insulated;
The boiler must be commissioned, i.e. set up to work as per its manual;
The Installer must explain how to use the system to the client;
The Installer must notify the Gas Safe Register.

Other factors that a gas engineer will include:

testing the gas system for leaks before any work begins;
how and where the condensate water will be drained;
what difference is required for the flue of a condensing boiler.

The procedure for fitting a second hand boiler is similar.

Cost of a New Boiler for Gas Central Heating System

New domestic boilers are available in the price range £500 to £2,000. It will depend on the details of the heating system and size of the house to determine what kind of boiler would be suitable.

In addition to the cost of the boiler and labour to fit it (with the procedure detailed above) there are a whole host of additional expenses which might be required, these should all be included in the quotation price supplied by the professional installer. It would usually take one or two days to replace a boiler.

Gas Engineer’s Estimate of Price

The heating system must be upgraded to comply with regulations if it does not already do so. The engineer who will install the new boiler needs to see the existing heating system to advise on what upgrading will be necessary. In addition the installer needs to see the house in order to recommend the most suitable boiler for the job. A quote over the phone is not practical.

The upgrade may require new size of pipework or relocating the boiler to a more suitable position. It may involve replacing gravity hot water with a fully pumped system. At the very least the U.K. legislation requires that a specific set of controls are in place for the resident to control the heating and hot water. These include timers for heating and hot water and thermostatic radiator valves.

How to Buy a New Boiler for Home

The choice of so many models of gas boiler on the market can seem bewildering. In fact only a small proportion of the whole range will be suitable for any particular house. Ultimately, one should choose a boiler in consultation with a qualified heating engineer. In many ways, choosing a good heating engineer, who will advise and do the installation, is more important.

The boilers can be divided along these lines:

Manufacturer or brand;
Type: regular, system or combination;
Efficiency: condensing or non-condensing;
Output measured in KWs (previously in B.T.U.s, the British Thermal Unit) .

How to Choose a Boiler Manufacturer or Brand

Some of the main companies with many years of association of producing quality boilers in Europe and Britain are (in no particular order):

Ideal Standard, Worcester-Bosch, Vailliant, Vokera, Keston, Baxi, Potterton.

All of the companies on this list have good reputations and a long history, but there are many more. Note, as with any business companies get bought and sold, so currently some of the boiler brands listed are actually owned by other companies, e.g. Keston is owned by Ideal Standard. To choose between them you need to compare not just their products and prices but their after sales care.

Boiler Manufacturers’ Warranty

A boiler should last more than ten years, so it is worth looking at more than just the price to differentiate between the goods on offer.

A two year warranty is standard, some will offer more, often five years.
Investigate the details of what is covered by the warranty
is the warranty only for parts or are labour costs covered
Does the manufacturer has a team of engineers who can rectify problems and service the boiler? What is the typical time wait for a call-out?

Different Types of Boiler & Efficiency

There are three different types of boiler and all of these types can be either high efficiency condensing boilers or less efficient non-condensing.

Regular and system boilers are preferable for larger houses where there might be many users drawing hot water simultaneously, or for properties where water pressure is low. Generally a system boiler may be simpler to install and, therefore, cheaper. Combi boilers are ideal for smaller properties especially if there is only one bathroom, these are usually the cheapest to install and are very efficient to run.

Regular Boilers, Including Back Boilers

Regular boilers produce hot water which is stored in a cylinder. A traditional heating system in Britain may have gravity fed hot water from a tank in the loft, but if the boiler is replaced the system must be changed to be fully pumped. This will continue to be served by a regular boiler.

Some boilers in the category are known as Back Boiler Units, as they are fitted behind a fire. Baxi are the only manufacturer of a condensing back boiler, currently.

System Boilers

The heating and hot water are both pumped inside a sealed system, there is stored hot water in a pressurised water cylinder. This heating system was only introduced to Britain in the 1980’s but was already common in Europe. It has the advantage over regular boilers in that the system is easier to install as more components are located within the boiler and there is no need for a tank in the loft.

Combination (Combi) Boilers

The water is heated by the boiler when it is drawn from the tap, there is no hot water cylinder. Combi boilers are the most common new boiler to be installed in Britain today.

What Boiler Size is Necessary?

The customer may think of size in terms of the physical space it occupies, the dimensions will not reflect the actual output of the boiler. Some are about the size of a washing machine and can be floor standing or wall hung. Many boilers are smaller. Keston boilers have a high output but are relatively small in size.

Boiler size is measured in terms of output. The biggest is not the best, the output should be calculated for a particular house, its construction and the number and size of its rooms. A boiler which is too big will not work well. A heating engineer will calculate the required boiler output.