Hot Water Gas Boilers

Save Energy

High efficiency condensing gas boilers can achieve seasonal efficiencies as high as 96%


The average efficiency of high efficiency condensing gas boilers is typically 14 to 18 percentage points greater than for non-condensing standard gas boilers. The condensing boilers have either a larger or a second heat exchanger, which saves the heat that would otherwise escape up the flue. The flue gases cool to the point that water vapour produced during combustion condenses, hence the name.

High efficiency condensing gas boilers can be easily fitted to most new and old heating systems. If gas supply is available, they are suitable for replacement of old boilers even in oil and liquefied petroleum gas (LPG)-fuelled heating systems. They are usually no larger than conventional boilers. You can buy them as either combination boilers, which heat up water on demand, or conventional boilers, where a separate hot water cylinder is required.


If your existing boiler is 10-15 years old then it most likely has a seasonal efficiency of between 55% and 65%. Replacing it with a new high efficiency condensing boiler will save you around a third on your heating bills straight away. It will also avoid expensive call outs. If you’re fitting a new kitchen or bathroom you may minimise cost and disruption by installing a new high efficiency condensing boiler at the same time.

To get the most out of your new high efficiency boiler think about combining it with new heating controls.

Appropriate controls let heating systems react to changes in temperature, provide different levels of heat in different rooms and switch hot water on and off at whatever times are specified by the homeowner.

Well-designed heating control systems will pay for themselves in less than four to five years. The more control, the greater the savings on energy and money – as much as 25% on the average heating bill.

To select the most appropriate gas-fired heating system and associated controls for your home, you are advised to contact a certified HVAC consultant to help you with determining the most suitable technical solution for your home assessing its size, construction type, geographical location and your heating requirements.