Heating system hydronic balancing reduces energy consumption

One frequently occurring problem is that of radiators not getting properly warm or heat being distributed unevenly to the various rooms in the house. Consequently it may be freezing cold in the kitchen and hot in the bathroom. This indicates that the heating system is not optimally adjusted. A process called hydronic balancing can solve this problem. This should be carried out by a heating installer.  Therefore, here you will find information for both the heating owner and the installer.

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Information for heating system owners

Hydronic balancing must be carried out after installing a heating system, be it in a new build or as part of a modernisation project. This enables the system to be adjusted to suit the individual heating requirements. 

Why is hydronic balancing necessary?

Hydronic balancing ensures that the correct amount of heating water is in each radiator at all times. As a result, the heat is distributed much more evenly within the building. This not only increases the level of comfort but also ensures that the energy used can be used much more effectively for heating and hot water. This is because hydronic balancing of the heating system increases energy efficiency by up to 15 percent. This has been proven by independent studies. If the heating system works better and more effectively, this also means that energy consumption and ultimately heating costs can be reduced.

In general, water always takes the path of least resistance. As a result, the radiators near to the heat generator are supplied with more heating water than those further away. Therefore the amount of water flowing through them must be limited. Hydronic balancing does this.

Is hydronic balancing mandatory?

There is no actual legal requirement for hydronic balancing. However, if a heating system is to be installed in accordance with the German heating system regulations of DIN 4701 and the German Construction Contract Procedures (VOB), hydronic balancing is mandatory. This applies in particular to heating systems for public tenders.

What's the procedure for hydronic balancing?

As previously mentioned, hydronic balancing is basically needed in order to supply all the radiators in a system with the exact amount of heat required for the respective room. To achieve this, the heating system must be adjusted according to demand. To do this, the flow of heating water through the pipework going to individual radiators, pump rate and heat generator settings must be precisely calibrated to suit one another. Hydronic balancing measures affect the heating pipes, all valves and all pumps.  

This ensures that no room is under or overheated and that heating energy is applied efficiently. Furthermore, hydronic balancing reduces noise nuisance caused by excessive flow speeds in the system. 

The individual steps of the hydronic balancing process

As a rule, a contractor is called out to carry out hydronic balancing. First of all, the contractor calculates the heat demand of the individual rooms. To this end, the output of the installed radiators and the actual heat demand of the occupants need to be determined. In addition, the contractor calculates the optimal flow temperature for the system as well as the required amount of water for each radiator. Special software is available for this purpose.

The individual system components are then adjusted on the basis of the data collected. These should be precisely coordinated with each other and be suited to the conditions of the heating system as a whole as well as the building.

Usually an oversized heating pump and a high flow temperature will ensure an even distribution of heat. But this also means an oversupply of heating water. The result is unnecessarily high energy consumption and excessive heating costs. The hydronic balancing process will also uncover any sizing issues such as these. Hydronic balancing can be considered a success once all radiators are operated with the same water pressure, regardless of their distance from the heat generator.  

Advantages of hydronic balancing

• Optimisation of the entire heating system
• Energy savings of up to 15 percent or financial savings of up to 300 euros per year
• Improved heating comfort
• Reduced flow noise

Potential savings for you

You can achieve greater efficiency without additional installation effort or material outlay simply by using the correct settings for heating circuits and heat generator, which pays for itself within the first year. The following example illustrates exactly what can be saved:

• Heating system with heat consumption of 25,000 kWh/a = 2500 m³ of gas/a or 2500 litres of fuel oil per year
• Savings through hydronic balancing: up to 325 m³ of gas/a, corresponds to energy cost savings of approx. 300 euros per year

Innovative solutions for hydraulic balancing

To take advantage of hydraulic balancing, Viessmann offers two solutions for detached and semi-detached houses. Digital and fully automated performance is possible with the ViCare radiator and floor thermostats. The optimization measure can be carried out in the traditional way with the Vitoset Balance Card.  

Automatic balancing with smart thermostats

With ViCare radiator and floor thermostats, hydraulic balancing is easier and faster than before. All that is required is to replace all conventional thermostats with intelligent ViCare components and connect them to the heat generator via the Viessmann electronics platform or a Vitoconnect interface. Control is then very simple via the ViCare app. Functions such as window-open detection and the ability to set individual time programs further increase convenience for residents.

Learn more about ViCare

Setting the flow rate with the Vitoset Balance Card

The thermostatic valves are adjusted with the Vitoset Balance Card based on room size and building age directly at the radiator. In just three steps, the flow rate is optimally adjusted and an even supply to the heating surfaces is ensured:

1. Place the Balance Card with the notch on the valve.
2. Turn the valve with the card and set the room size according to the building age.
3. Transfer the sum of the individual valve settings to the parameterization of the heating pump.