Energy Efficient Condensing Gas and Oil Fired Boilers
Harpenden, St.Albans, Hemel Hempstead, Welwyn Garden City, Watford and Tring

Condensing boilers are the most energy efficient central heating boilers on the market today. They can be up to 10-15% more efficient than a modern conventional boiler and up to 30% more efficient than older boilers, so the energy saving and the impact on your fuel bills can be significant.

They achieve this high level of efficiency by removing the heat from the fuel it is burning and also cooling the products of combustion, which are normally wasted up the flue in conventional boilers, so much so that the water vapour in them turns into liquid. This happens at around 55°C. For a boiler to cool the flue products this much, it has to have a larger, more efficient heat exchanger than traditional boilers. This does mean that condensing boilers cost a little more, but the resulting fuel savings mean the extra cost will normally be recovered in 2-4 years.

There is also another benefit obtained by the water vapour turning into liquid; it gives up energy, which is called latent heat. This latent heat adds to the rest of the heat to make the overall efficiency of a condensing boiler approximately 15% greater than a modern non-condensing one. The more efficiently the boiler runs, the less fuel it uses, therefore the less carbon dioxide it produces and the less it costs to run.

For more information on condensing boilers, please see Condensing Boilers FAQ or visit SEDBUK (Seasonal Efficiency of Domestic Boilers in the UK) for some useful facts and figures.

Current Regulations

The rules for gas and oil installations are designed to protect you and your family and the standards are regularly improved. From 1 April 2005, all central heating boiler installations fall under the control of building regulations (the change applied to oil fired central heating boilers from 1 April 2007).

If you are planning to install or replace an existing gas or oil fired boiler, you need to choose a condensing boiler with either an ‘A’ or ‘B’ efficiency rating (A= greater than 90%, B= 86%-90%).

If there are exceptional circumstances, for example, where it is not practical or economic, a non-condensing boiler can be fitted and in this case an ‘exception certificate’ will be provided.

Features of Condensing Boilers

• The natural buoyancy of the exhaust gases is lost when the temperature is brought this low so a fan is needed to compensate for the lower convection flow.
• The condensation process produces a liquid water, the condensate, which is acidic (due to sulphur and nitrogen impurities), and requires the use of special materials and the addition of a fluid draining system.
• The exhaust will appear as a continuous plume of steam.
• Fitting a condensing boiler to an existing system will normally require the system to be power-flushed so existing sludge does not enter the new boiler.

Advantages of Condensing Boilers:

• Less carbon dioxide produced so they are more environmentally friendly
• Use less fuel
• Lower monthly fuel bills
• High efficiency

Disadvantages of Condensing Boilers:

• Higher initial investment
• Fewer qualified experts – 3 Counties Heating’s engineers are qualified!