Bosna i Hercegovina

THB actuator – your way to efficient underfloor heating


Self-regulating actuator – why is it worth it?

A well-adjusted hydraulic heating system ensures the ideal temperature in the household rooms. It guarantees the feeling of comfort, has a positive influence on our health, and generates savings. A tool that offers a proper setting for underfloor heating system operation is THB self-regulating actuator.

What is a THB self-regulating actuator and how does it work?

The THB23030/THB2430 actuator is a modern, manifold-mounted self-regulating device for surface heating systems. Its precision is incomparable to others: by constantly measuring at the beginning and end of the heating loop, it maintains the optimum temperature difference and adapts the water flow to the building’s needs.


At the supply and return of the corresponding underfloor heating loop, the THB actuator has contact sensors that measure the temperature and automatically adjust the actuator to maintain the correct supply/return temperature difference (ΔT).

Why is it important?

It is estimated that about 90% of central heating installations are not hydraulically adjusted. This means that the distribution of the heating liquid stream is incorrect – the house is unevenly heated (overheating/underheating also within one zone). This results in energy losses, higher bills and inappropriate interior microclimate, which causes worse mood of household members.

Why does this happen?

There are many reasons (more on that below), but one of the most common is carelessness at the installation stage. Due to a large number of tasks and a fast working pace which leaves little time for precision, some installers do not pay proper attention to the adjustment of the underfloor heating they are setting up. Unfortunately, this results in the future low efficiency of the heating system. The THB self-regulating actuator is the solution to this problem, because by using it, you gain ideal thermal comfort with minimal energy consumption.

Hydraulic balancing (hydraulic calibration)

Hydraulic balancing of the heating system allows an even distribution of the heat medium (heating fluid), in accordance with the building design. This eliminates unwanted overflows and underflows, which reduces heating costs. The hydraulically balanced system is based on real fluid flows. Even the longest underfloor heating loops are provided with an adequate flow rate – there is no cooling of the room. And the shortest loops are not exposed to excessive flow rates – no overheating is taking place. All loops have the right heating medium flow rate, so the system is comfortable to use and energy-efficient. Hydraulic calibration is very important in buildings that are being thermally upgraded and in low-parameter installations powered by heat pumps or condensing boilers.

Factors that disturb the hydraulic balance of a central heating system

Why are most installations poorly hydraulically balanced? This is caused by many factors that are not always up to you. The most common are:

  • lack of measurements that determine the power requirements of the system
  • loops of different lengths and densities (uneven temperature in the heating zone)
  • quality and execution of all underfloor heating layers: the installation consists of many elements (pipes, concrete, foil, polystyrene, sand) – their quality affects the whole system
  • type of the floor (ceramic/stone tiles, panels, wood, carpets, rugs – depending on the material used, heat will be transmitted and felt differently)
  • interior design and arrangement of furniture – especially large-size furniture that occupies a large area such as beds and closets – may disturb heat transfer through the floor
  • unavoidable consumption of flow meters: as they are used, the original settings are no longer effective because the mechanisms lose their efficiency
  • drastic weather changes: if, after adjustment (fine-tuning), there is a big change in the weather conditions, the set flow rates may not be sufficient to heat the room quickly enough

Your benefits when purchasing a THB

First, quick installation (only 3 steps). You just need to install the actuator on the manifold, and connect the sensors and power supply.

Second, convenience and time-saving. No need to regularly check and tune the system – the actuator does it for you.

Third, easy fit; THBs can be used on manifolds with and without flow meters (rotameters). They fit the most common thread size M30x1.5. What is important, when you decide on a manifold with flow meters, you have to expect a higher price of the device, but without a guarantee that the system will always work reliably. Rotameters can be problematic; after some time of use, they wear out and stop working properly. Using THB actuators this risk disappears because you do not need flow meters at all. You can buy a cheaper manifold and ensure you have the best-regulated heating system. This is really a big economic and functional advantage.

You get efficient heating. The underfloor heating works efficiently with different loop lengths and even with changing interior design, and gives an even temperature throughout the zone.

Other advantages of THB

  • fast open and close time (approx. 30 seconds)
  • low power consumption (less than 0.5 W)
  • durability of used materials
  • long lifetime
  • innovative control with THB

The effectiveness of the device has been confirmed by technical tests. The iTG Dresden[1] confirmed that the THB self-regulating actuator correctly balances an underfloor heating system. In cooperation with iTG Dresden we tested and improved our actuator.

REMEMBER: Reduction of energy consumption after hydraulic balancing is about 10 – 20 kWh/m2 per year, which means savings of around 220 EUR for a house of 100 m2. The benefits of buying an actuator are therefore measurable, not hypothetical.

[1] Institute for Technical Building Equipment ITG in Dresden, offering research services in the field of technical building equipment.

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