Condensing boilers basically utilise modern technology to extract more energy out of each unit of fuel you burn. They are therefore more efficient than older type boilers often converting more than 88% of their fuel into heat compared to around 78% for conventional boilers.
Vaillant have been at the forefront of heating technology for over 130 years.
Their high efficiency condensing boilers can achieve efficiencies of 90%.
If your existing boiler is more than 15 years old, a high efficiency condensing boiler from Vaillant could save you as much as 35p in every £1 on gas used for heating and hot water.