The benefits of modernising heating systems

The benefits of modernising heating systems

Achieving savings through innovative condensing boilers. Thanks to energy-saving and passive house standards, heating systems in modern buildings use much less energy than they did even just a few years ago.

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  • End customer / Investor

Gas condensing boilers: an energy-efficient alternative

Gas condensing boilers offer many operational and financial benefits, and live up to both the latest market requirements and investor expectations. In conventional gas boilers, the heat energy from the exhaust gases is transferred to the heating water via a heat exchanger, cooling the exhaust gases to a specific temperature (such as 180°C). In thermodynamics, this part of the energy is called sensible heat. Exhaust gases contain another form of heat energy called latent heat. The latent heat is present in the steam produced during combustion. This energy is irretrievably lost in conventional gas boilers and escapes up the flue.

Gas condensing boilers harness this additional heat energy from the condensation of the steam using a specially designed heat exchanger that has a particularly large surface area. After the sensible heat has been recovered from the exhaust gases, these gases are cooled down further. As soon as the exhaust gas temperature is reduced to a value below the condensation temperature (dew point), the steam condenses. Condensation heat is released and transferred to the heating water in a heat exchanger.


Due to the special design of the heat exchanger, condensing boilers are able to obtain more heating energy than conventional boilers. Condensing boilers save energy and also provide a convenient, low-maintenance way of heating buildings.

Outstanding efficiency through innovations

One innovative example is the aluFer heat exchanger in UltraGas boilers. This is made of aluminium on the inside and stainless steel on the outside. The special lamella design of the aluFer heat exchanger results in a fivefold increase in the surface area for heat transfer. As a result of this process, exhaust gases can be cooled efficiently, making it possible to recover up to 20% of the energy used.

Another innovative solution used in UltraGas boilers involves separate returns for high and low temperatures. Water from heating circuits with different temperatures can be channeled through the boiler’s separate return connections, resulting in optimum conditions for effective condensation in the lower part of the boiler – and in turn leading to greater energy recovery from the exhaust gases. This solution contributes up to an eight per cent increase in the efficiency of UltraGas boilers compared to other condensing boilers.


The burners in condensing boilers are specially designed and made of materials with maximum heat resistance, ensuring a long service life and the very best operational reliability. The radiant burners in the UltraGas range of gas boilers operate with the UltraClean system, which precisely adapts the burner output in line with current demand. It reduces the switching frequency and ensures clean, low-emission and efficient combustion.

Reduced consumption through intelligent control

The automated system operation also plays a major role in achieving a high degree of efficiency. To achieve optimum energy consumption, the heat output of a boiler must be adapted to the current demand for heating energy in the building. To do this, the outdoor conditions and upcoming changes in the weather must be taken into account. With its intelligent TopTronic E control system, Hoval provides a modern solution that is compatible with all Hoval heat generators. A web browser or smartphone app can be used to control individual boilers as well as cascades of multiple boilers. Working in conjunction with solar collectors, the TopTronic E control can forecast solar radiation based on collected weather data and adjust the heating programme accordingly. This further reduces gas consumption.

The benefits at a glance:

  • Excellent energy efficiency
  • Outstanding efficiency
  • Financial savings
  • Environmentally friendly
  • Low maintenance requirements
  • Long service life
  • Excellent operational safety

By modernising your heating system, you too can benefit from all this.