Gas heating with gas condensing boiler or gas condensing boiler 

For convenient heat generation with natural gas, Viessmann offers various technologies that meet a wide range of needs. For example, for gas heating in new builds or modernization projects, for owner-occupied apartments, single-family homes or even for large projects in the housing industry. Gas condensing boilers are particularly suitable for use in new buildings. These are extremely compact and wall-mounted units that can fit in almost any room.

If a solar system is to be connected for DHW heating, on the other hand, gas condensing boilers with an integrated solar heat exchanger are recommended. The floorstanding units are already designed for bivalent operation. Technically, Viessmann gas condensing boilers are state of the art and cover an output range from 2 to 100 kW. They are therefore able to supply heat efficiently and reliably to detached, semi-detached and small apartment buildings at all times.

Condensing boilers with gas are also available in larger dimensions. These are mainly used in buildings with a high heat demand. These are usually apartment buildings, public and commercial buildings. Thanks to the cascade function, several devices can be quickly connected to form a unit and also provide reliable heat in this area.

The picture shows a gas boiler on the wall

Protecting the climate and the environment - for example with a gas condensing boiler

Combining climate protection and financial relief. This is possible with the use of condensing boiler technology. Because what makes this technology so special is its highly efficient use of energy. While conventional heating systems simply let part of the energy contained in the fuel escape unused, gas condensing heating converts the energy content of a fuel almost completely into heat. Anyone who heats with a gas condensing boiler, for example, keeps heating costs at a low level in the long term and at the same time reduces the burden on the environment. Because less combustion also means less CO2 emissions.

All Viessmann gas condensing boilers meet the EU-wide requirements for efficient condensing technology. 98 percent and more of the energy used is converted into heat. With this unbeatably high efficiency, every operator of such a gas heating system makes an active contribution to climate and environmental protection.

Using future-proof heating technology today

The calls for resource-saving heating technologies are getting louder and louder. New gas condensing boilers should not only be clean, but also sustainable. In response, Viessmann has already built the future into its gas condensing boilers. Thanks to combustion control, the gas condensing boilers automatically adjust to different types of gas - including biogas admixture. In this way, the heating systems sustainably meet the requirements for resource-saving heating technologies.

Another argument for choosing a gas condensing boiler is that energy does not have to be stored in the house. The compact gas condensing boilers are space-saving and leave additional room in the utility room or basement.

Save up to 35 percent energy by replacing outdated gas heating system

In Germany alone, there are still around two million heating systems in operation that are more than 25 years old. By replacing these boilers with highly efficient condensing boilers, end users could save a lot of energy with modern gas heating - up to 35 percent in combination with solar technology. In arithmetical terms, this would be ten percent of Germany's total energy consumption, while at the same time reducing CO2 emissions by 54 million tons a year. We have summarized what you should look out for when replacing a boiler in the section Modernizing gas heating systems.

The picture shows a solar thermal system with which a gas condensing boiler can be combined.

Combine the new gas condensing boiler with solar panels

The free energy of the sun for heating support and domestic hot water heating is still too little used. Today, every new gas heating system such as the gas condensing boiler should also be combined with solar collectors to utilize free solar energy. When operating the gas heating system in conjunction with Vitosol solar collectors for backup heating, subsidies can be applied for from the KfW Bank and the requirements of the EEWärmeG and EWärmeG in Baden-Württemberg can be met. The building owner can apply for public subsidies for this investment. Current information on this can be found in our subsidy database.

Moderne Gasheizung - So funktioniert Brennwerttechnik

Modern gas heating - resource efficiency with condensing technology

Condensing technology not only utilises the heat generated by combustion as a measurable temperature of the hot gases (net calorific value), but also the water vapour content (gross calorific value). Condensing boilers are able to extract almost all of the heat contained in the flue gases and to convert it into heating energy.

Condensing boilers use high performance heat exchangers. These cool the flue gases before they escape through the chimney, to the extent that the water vapour contained in these gases is deliberately condensed. This releases additional heat which is transferred into the heating system.

With this technology, a gas condensing boiler achieves a standard seasonal efficiency [to DIN] of up to 98 % (relative to Hs). Condensing boilers are therefore particularly energy efficient, looking after both your wallet and the environment.

Calorific value (Hs)

The gross calorific value (Hs) defines the amount of heat released by complete combustion including the evaporation heat latent in the water vapour of the hot gases.


The MatriX gas burner

The MatriX gas burner represents a milestone in Viessmann heating technology. The use of the stainless steel MatriX gauze endows it with a long service life. The burner is resistant to high temperature loads.

Gas condensing boiler

With condensing technology, not only is the heat from the combustion of fuel oil or gas utilised, but also the heat that, with non-condensing heating technology, would otherwise escape unused up the chimney. Condensing boilers extract almost all of the heat latent in flue gases and convert it into additional heating energy. To do this, Viessmann condensing boilers are equipped with stainless steel Inox-Radial heat exchangers, which cool the flue gases before they are routed into the stack, to the extent that the water vapour contained within them is deliberately condensed, transferring the additional heat released into the heating system.