Condensing boilers are highly efficient technologies, capable of providing heat to buildings as well as domestic hot water. They are called ‘condensing’ because they ‘condense’ the water vapour produced in the combustion process into liquid form. The heat of the water vapour is reused to warm up the cold water entering the boiler. This process ensures that most of the energy produced during combustion is recovered to heat the building.
The most common condensing boilers operate with gas, while condensing boilers running on other fuels are especially suited for off-grid buildings. Condensing boilers can easily be teamed with a solar thermal system to reduce fuel consumption by 10-20%. The use of condensing boilers with green gases (such as biomethane, hydrogen and bio-LPG) and fuels would enable further CO2 emissions reductions, moving us closer to our EU-wide goal to decarbonise the building sector by 2050.
Our market data shows that condensing boilers running on gas remain the first choice in efficient heating technology in Europe. They are particularly suitable for the modernisation of existing appliances as they can rely on an existing, and extensive, gas network. More than 4 million of them were sold in 2018, bringing substantial energy efficiency gains compared to the old and inefficient systems they replace. The highest energy efficiency gains are obtained by installing a condensing boiler and adjusting the system where needed thanks to hydronic balancing and the possible addition of heat emitters.