Should you modernise an old heating installation if it is still operating?

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How much could you save by investing in innovative condensing boilers?  

Regardless of whether we are talking about public buildings, single-family houses or large industrial facilities – determinants of modernity are low operating costs and minimal impact on the environment. 

New buildings are designed and executed in an energy-saving standard, and in passive standard, where far less energy is used for heating than several years ago. The investors’ expectations and market needs are met by gas-condensing boilers which have many operating and financial benefits.

We can show you how much you can save by replacing old equipment with the specific example of  a production hall. But let's start from the beginning...

Condensation technology – what is it?

In conventional gas boilers, heating water in an exchanger takes energy from flue gases which are cooled down to the specific temperature (e.g. to 180 °C). In thermodynamics, this part of energy is called sensible heat. In their form, flue gases contain an additional amount of heat, called latent heat. This latent heat is contained in water vapor created during combustion. This energy in conventional gas boilers is irretrievably lost and runs outside via flue. Gas-condensing boilers use this additional amount of heat from the condensation of water vapor, via a special heat exchanger with a particularly large surface area. After the sensible heat is separated from flue gases, it is cooled. By lowering the temperature of flue gases to a value lower than the condensation temperature (dew point), water vapor condenses.  During water vapor condensation process, condensation heat is released and transferred to the heating water in a heat exchanger.

Condensation technology

Thanks to the suitable structure of the heat exchanger, condensing boilers gain more heating energy than conventional boilers. As well as energy saving, condensing boilers also ensure comfortable and maintenance-free building heating.  

Innovative solutions in condensing boilers

Over the years, designers of gas boilers have introduced a number of innovative solutions to improve condensation technology. High efficiency of condensing boilers was achieved thanks to the modern designs of heat exchangers and the materials from which they were made. Many manufacturers began using aluminum-silicon heat exchangers which are characterized by high efficiency and small dimensions. Aluminum has a higher thermal conductivity and heating surface, which allows for obtainment of greater power than in the case of a stainless steel heat exchanger. Such solution allows for constructing complex surfaces of heat exchange which greatly increased efficiency of the gas-condensing boilers.

An example of innovation is the heat exchangers in the UltraGas® : aluFer®. AluFer®  is made of aluminum on the inside and stainless steel on the outside.  AluFer® increases heat receipt from flue gases by 20 percent in comparison to steel heat exchangers and ensures uniform heat exchange. Thanks to this process, flue gases may be easily and deeply cooled.

Another innovative solution used in UltraGas® boilers is the introduction of a separate circuit of high and low temperature. Water from circuits with different temperatures may be introduced to separate return stub pipes on a boiler. As a result, in the lower area of the boiler has perfect conditions for effective condensation – which translates into greater energy recovery from flue gases. This solution contributes to an 8 percent increase in efficiency of UltraGas® boilers - compared to other condensing boilers.

Burners of condensing boilers are specially designed and made of the best heat-resistant materials, guaranteeing sufficiently long service life and operating safety. Radiant burners in gas boilers UltraGas® use UltraClean® system which exactly adapts the burner capacity to the current requirements.  The system reduces switching frequency and ensures clean, low-emissions and efficient combustion.


Equally important way of obtaining high efficiency of boilers is automation of operation of the equipment. It is necessary to adjust the heating power to the current heating energy demand in the building - taking into account the current outside conditions and, equally important, upcoming changes in the weather. An example of such a solution is the intelligent control unit TopTronic®E which was introduced for all Hoval heat sources.  With one controller, we can control operation of individual units as well as those operating in a cascade - all this from the level of a web browser or an application for smartphones. If the heating installation is extended with solar panels, the TopTronic®E controller, based on weather readings, predicts the sunlight degree and adapts the heating program appropriately - thus reducing gas consumption.  


Case study – dental materials factory in Lichtenstein

“We should have done this much earlier- It came two or three years too late when I see how much we could have been saving” Mr. Fussi (Ivoclar facility manager) said. These words speak for themselves!

boiler room Hoval_ Ivoclar

The old central heating plant with a non condensing boiler was only about 10 years old!

Hot water boiler (ST-plus): 1 x 2900 kW 
Fuel: Natural gas
Annual fuel consumption:

480.000 m3/a

Decision was to install Gas-condensing boiler: 2 x UltraGas® (1440D): 2880 kW
Investment cost (boiler) ca. 400.000 sFr.
Annual saving of operation costs with UltraGas® :          

60.000 sFr./a

ROI:   6.6 years
Cost saving after 20 years ca. 1.200.000 sFr.
Eco-audit (CO2 –savings) 240 t/a
After 20 years

4800 t

The energy savings with the new UltraGas boilers is about 20 to 25 % per year.

The need to reduce energy demand and to reduce the rising operating costs of buildings - translates into the popularity of modern condensing boilers which displace less economical solutions which are burdensome for the environment.  This equipment, thanks to the use of the highest quality sub-assemblies, guarantees the most effective use of gas fuels. Modern condensing boilers work well in modernized installations and in new buildings - regardless of whether we are talking about single-family houses, multi-family houses or large buildings.  

If you are interested in modernization with the use of condensation technology, let us know, and share the article! 

Günther Köb

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