Discounted Heating for
Boilers, Radiators, Bathrooms & Showers

Jargon Buster

• Fuel Options
• Heating Systems
• Boiler Types
• Flue Types
• Efficiency
• The New Legislation - April 2005
• Glossary

Fuel Options[top]

Natural Gas

Natural Gas is a clean fuel, burning with by-products of steam and carbon dioxide,  and having the least damaging effect on the environment of all of the other fossil fuels.  It is currently the cheapest option in terms of running costs. (see below) Natural gas is  mains supplied, thus requiring no storage. The downside is that the supply may not be  available to everyone. It is a legal requirement that a gas boiler is fitted by a CORGI  registered engineer.

Oil

This is the most popular alternative to gas, used, for example, when location means no  mains gas supply is available. Oil is not quite the cheapest alternative, but is a  competitive option, although prices can change seasonally and vary with location. Oil is  not the cleanest fuel and can contribute to acid rain amongst other environmental effects.  The use of oil requires a storage tank. OFTEC registered engineers are most suitable for  fitting oil boilers, although unlike gas this is not a legal requirement.

LPG

Liquid petroleum gas has many of the same advantages of mains gas but is considerably more  expensive to use. LPG can also be used with other household equipment such as cookers and  fires. As with oil, LPG requires a storage tank, or can be provided in replaceable  cylinders. The range of LPG boilers available is considerably less than mains gas. Gas  boilers can be converted to LPG with the appropriate conversion kit. It is a legal  requirement that an LPG boiler is fitted by a CORGI registered engineer.

Electricity

Although conveniently available to practically every home, electricity still ranks as  the highest costing fuel for heating. However use of electricity for central heating and hot  water in this country is still the second most popular choice after natural gas. Electricity  appears to the end user to be 100% efficient since no heat is lost through a chimney with  fossil fuels. However since much of the country's electricity is provided by fossil fuel  burning power stations it is here that the environment is affected.

Heating Systems[top]

There are two categories of heating system; Traditional Systems and Combination Systems. Boilers in  each system are used to both heat the hot water and  provide the heat to the radiators. They differ in  the way they heat the hot water, and in the type of radiator system. Traditional boilers can operate either  an open vented or a sealed radiator system depending on the boiler type.

Traditional

Traditional boilers are used to heat the radiators, aswell as the domestic hot water that is  held in a cylinder, usually located in an airing cupboard. This type of system is best if there is a high  demand for hot water since the storage tank can absorb the impact of several hot water outlets being used  at one time. Traditional boilers can be an advantage over Combination Systems if the mains pressure is  too low to produce a decent flowrate at an outlet in the property.

The central heating circuit is generally an open system, unlike with Combination Systems. As the water  in the radiators warms it expands and overflows into an expansion tank in the loft. As the radiators cool  again gravity drives this overflow back into the system to keep the pressure up in the radiators.

A Traditional Heating System

Traditional Systems can sometimes be converted to have sealed radiator systems by adding an expansion  chamber to the circuit. System boilers come complete with this expansion chamber, sometimes  built into the boiler, eliminating the need for the expansion tank in the loft of the property.  They are space saving, less complicated to fit and are more efficient and a fully open vented traditional system.

Combination

Combination Systems use Combination, or 'Combi', boilers. Combi boilers heat the hot water on demand  by a heat exchanger in the boiler. There is no need for a hot water storage tank. Installation is often  quicker and cheaper than a traditional type system.

Combi boilers also have a sealed radiator system, that needs to be pressurised when the heating is off.  There is no need for an expansion tank in the loft for the heating. Combination Systems suit a household  where hot water is not in great demand. The mains inlet pressure determines the pressure of the hot water  at an outlet.

A Combi Heating System

Lack of a hot water storage tank and an expansion tank means that Combi systems occupy less space and  can be easier to fit and maintain. Hot water is essentially an endless supply, although demand from several  outlets at one time can reduce the flowrate at each. These systems are highly efficient because no heat is  lost from water sitting in a storage tank, however in colder times there can be a delay in receiving hot water  from a tap due to the initial inflow to the boiler being cooler. Combination systems are best suited for  couples or small families where there is a low demand for hot water i.e. less than two bathrooms. Combi  boilers are useful space savers because they don't require a hot water tank, so if the boiler is for a flat  or a house with a loft conversion then a combi boiler would be the best choice.

Boiler Types[top]

Condensing

Condensing boilers, also known as High Efficiency  boilers, although more expensive to buy, have very  efficient heat exchangers. These are the SEDBUK A rated boilers. In larger properties the initial outlay for  the purchase may be greater than with a conventional boiler, but this cost can be recovered in a few years  due to the efficiency. Other considerations are a drain to remove the condensate, and a steam from the outlet  may be an annoyance or an eyesore. Both Traditional and Combination Systems can use Condensing boilers.

Standard Efficiency

Standard Efficiency type boilers are available for traditional or combination systems. Standard Efficiency boilers  operate at lower efficiencies than condensing boilers, but the initial purchase cost is less than  High Efficiency (Condensing) models. New  leglislation, introduced in April 2005 in England and Wales, strictly controls the number of homes  that can be fitted with Standard Efficiency boilers.

BBU

Back Boiler Units are fitted into fireplaces that may already have an existing fire front. This type of  boiler is a space saver, but higher outputs can be an issue because of the size limitations. Other  considerations are a path to the outside for ventilation. BBU are used in traditional systems, and cannot  have a sealed radiator system because their power output is not great enough.

System (or Sealed System)

System boilers, or 'Sealed System' boilers, are used in traditional system with a sealed radiator circuit.  They have the expansion chamber included in the set or will have the components built in. For this reason  some system boilers are larger than other types, and are best for homes where hot water demand is high.

Floor Standing

These can be traditional or combi boilers and are the type that are seated on the floor. Floor Stading boilers  can fit in spaces between kitchen units or, in larger homes, in a pantry or a garage.

Wall Mounted

Wall Mounted boilers are the opposite type to the Floor Standing variety, are smaller and generally cheaper.  Usually they are more compact and in some instances may even be small enough to be positioned inside a wall mounted  kitchen unit.

Flue Types[top]

A flue is a pipe or chimney that is used to vent the waste gases, from the combustion process in the boiler,  to the outside of the property. The waste gases are mostly carbon dioxide and steam. There are several types  of flue, some boilers accommodating all types and some just one.

Room Sealed Flues, RS (Fan Flues, FF)

These are by far the most common flues to find on a modern boiler. Boilers with a room sealed fanned flue  can only be fitted to an outside wall. A double skinned pipe draws air in from outside and feeds waste gases  back out again. In this situation flue gases cannot escape directly back into the room, and is therefore a  safer option. Room sealed flues can operate through the natural draught of the air, or may be fan assisted  to allow for longer flue runs.

Open Flues, OF (Chimney Flues)

Open flues draw air in from the room in which the boiler is located. This air is used in the combustion of  fuel and is then vented to the outside of the property. Open flues can operate through the natural draught of  the air, or may be fan assisted to allow for longer flue runs. Use of open flues is most common in BBUs in an  existing fireplace.

Balanced Flue, BF (Conventional Flue, CF)

Increasingly less common the balanced flue contains a baffle to control the flow of air in and out of the  ducting.

Efficiency[top]

Under the Government's Energy Efficiency Best Practice Programme a standardised method of defining product  efficiency was called for. The result was SEDBUK or Seasonal Efficiency of Domestic Boilers in the UK (see www.sedbuk.com). This is a measure of the average annual efficiency  of a product given influences such as the season. The scale goes from A to G, A being the most efficient.  You can calculate the size of boiler best suited for your needs at this address http://www.sedbuk.com/whole_house.htm.

The New Legislation - April 2005[top]

The domestic heating sector is responsible for one third of the United Kingdom's  carbon dioxide emissions. The Government has made changes in the Building Regulations  in a bid to contribute towards the global move to combat carbon dioxide emissions and  reduce global warming.

From the 1st of April 2005 all new gas boilers installed in England and Wales will be  Condensing Boilers of SEDBUK rating A or B. From the same date details of all boiler  installations must be provided to the local authority building control (LABC).

There are times when it is too inconvenient or too expensive to fit a new Condensing  Boiler into a property. In these situations exceptions can be granted and a standard  efficiency boiler can fitted legally. The procedure to decide whether an exceptional  circumstance has arisen is a points system based on the following:

• The property type
• The fuel
• Whether the boiler needs to be moved
• The need for an extended flue
• The need for a condensate pump or soakaway

For more information visitPart L of the Building Regulations (Revised 2006).

Glossary[top]