Gas condensing boilers

Efficient heat generation

A condensing boiler is a high efficiency modern boiler, capable of generating the necessary heat supply for central heating and for domestic hot water. Its name comes from the water vapour produced in the combustion process which ‘condenses’ back into liquid form, and is reused to pre-heat the cold water entering the boiler. This makes the gas condensing technology highly convenient, resource- and cost-efficient for heat generation.

Condensing boilers cover almost all output ranges. Wall-mounted units deliver up to 100 kW. With boilers in a cascade system (several appliances connected to each other), the output can be increased to several hundred kilowatts. Floor-standing units can supply nominal outputs of more than 10,000 kW.

Condensing boilers running on natural gas are often the first choice both for new installations and for refurbishment of existing central heating systems across Europe. They can be easily combined with renewables such as solar thermal systems.

Heating and domestic hot water

A combination boiler (or 'combi' boiler) is called in this way because it heats water for the central heating system and for the domestic hot water taps on demand (instantaneous hot water). A 'System' or ‘Open Vent' boiler provides heated water for the central heating system and is connected to a hot water cylinder (storage tank) to provide hot water to the taps. The choice between these two options depends on various factors such as space, mains water pressure, number of bathrooms.

Perfected technology

For more than twenty years, the gas-fired condensing technology has been constantly advancing: increased comfort and energy efficiency, reduced emissions and noise levels, improved design and reduced size to fit any building setting. Gas-fired condensing devices can also cope very easily with highly fluctuating requirements for heating and hot water.

For guaranteeing high efficiency, it is essential that the condensing gas boiler is installed, serviced and repaired by qualified personnel.


  • Increased energy efficiency & reliability
  • Easily installed and maintained
  • Suitable for modernisation in existing buildings and new buildings
  • Relying on the expanding gas network
  • Easily combined with renewable energies
  • Well established and continuously perfected technology