Boiler Types Explained
A conventional boiler is one that is installed with a conventional system. A typical conventional system incorporates a boiler, associated controls, a feed & expansion tank and a hot water cylinder fed by another coldwater storage tank.
Flues for this system can be conventional into an existing chimney with a flue liner, balance flued or fan flued.
Condensing Back Boiler
As above but the boiler is situated behind an electric fire.
Flues for this system are conventional into an existing chimney with a flue liner.
This differs from a traditional or conventional boiler in two important respects. Firstly, many of the major individual components of the heating and hot water system are built in, which means that installation is quicker, neater, easier and less costly. Secondly, the hot boiler water is pumped through the system to the radiators and hot water cylinder, resulting in fast response and more economical running costs. With this system an unvented hot water cylinder can be incorporated to give large quantities of hot water at mains pressure which is suitable for larger properties.Flues for this system are fan flued.
Combination Boiler (Combi)
The combi is an ingenious space-saving idea, which is increasingly installed in British homes. In fact the combis now account for more than half of all the domestic boilers installed in the U.K. each year. By incorporating both a very efficient water heater and an economical central heating boiler within one compact unit, the combi eliminates the need for the hot water storage tank and other familiar components of a conventional heating system. This can not only significantly reduce hot water costs but also has the major benefits of providing hot water at mains pressure. So you can enjoy power showering without the need for a pump. Flues for this system are fan flued.
Condensing Boilers (High Efficiency)
Condensing boilers can be Combi’s or System and are over 90% efficient, (Energy Efficient band A). Modern standard efficiency boilers range from 78% to 80% efficient band F to D.
The only additional installation cost is a plastic overflow pipe which discharges the condensate. Careful consideration must be given to the position of the flue terminal as it will plume. This pluming is quite safe as it is only caused by water droplets in the flue gases.
Not only are these boilers cheaper to run but, with extremely low emissions of CO2 (Carbon Dioxide) and Nox (Nitrogen Oxide), they are also environmentally friendly. A typical Semi detached property with an old heavy weight existing boiler would cost about £397 per year on fuel, the same property converted to a Condensing model would cost only £242 per year, a saving of £155 per year.