HERZ as a problem-solver
Clean retrofitting of underfloor heating in existing buildings
In practice, the desire for greater comfort is increasingly reflected in the retrofitting of underfloor heating – for example, in bathrooms, toilets, hallways or as part of a flat or floor-level refurbishment. In most cases, this applies to existing radiator systems and thus presents a key technical challenge: the seamless integration of surface heating systems with low flow temperatures into a high-temperature circuit. HERZ offers various solutions for this – tailored to different renovation scenarios and requirements.
As is well known, radiators operate at higher flow temperatures than underfloor heating systems. Underfloor heating cannot therefore simply be integrated directly into an existing radiator system. This raises a typical question for plumbers in day-to-day renovation work: How can additional underfloor comfort be implemented in a technically sound manner when space is limited and existing systems must be taken into account – without resorting to improvised, bespoke solutions that may cause further challenges later on? An additional distribution circuit, as would be used in a new build, would often be too costly and not economically viable in renovation projects where small areas are to be fitted with underfloor heating.
“It is particularly rare to find the ideal situation in renovation projects. Often, various factors arising from an existing system combine to tempt the installer into a complex and, at the same time, avoidable custom design,” reports HERZ planning consultant and sales representative Leon Čutura, speaking from practical experience. He himself has frequently been able to help his customers with time-saving solutions that make technical and economic sense. “The key is to find solutions that can be implemented quickly on site and, at the same time, do not create any additional challenges in the long term during operation. This is precisely the aim: to provide suitable systems for a variety of renovation situations,” he concludes.
Solution for individual room control: HERZ Floorfix Compact
If the retrofit of underfloor heating is for a clearly defined area such as a bathroom, hallway or toilet, HERZ Floorfix Compact offers the ideal solution. The product, which is supplied as a flush-mounted installation kit comprising an EPP mounting box and a cover plate, is designed for individual room control via a thermostatic valve and a return temperature limiter.
The return flow temperature limiter ensures that the fluid temperature is adjusted to meet the requirements of the underfloor heating circuit, so that a comfortable floor surface temperature can be achieved. At the same time, the user can set the room temperature as desired using the thermostatic head. In addition to its technical function, HERZ Floorfix Compact is designed to be visually timeless and suitable for any room.
Solution for combining radiator and underfloor heating: HERZ Room Temperature Control Set
Another real-world renovation scenario involves combining radiator heating with underfloor heating in a single room. This situation often arises, for example, when a customer wishes to keep their towel radiator in the bathroom whilst also installing underfloor heating. This requirement calls for a solution that can control both heating elements – the radiator and the underfloor heating – separately and independently.
This is where the HERZ Room Temperature Control Set comes into play. The control set is designed to regulate the floor temperature via underfloor heating whilst a radiator is in use. The set comprises a dual-connection manifold, a shut-off valve, a TS-98V thermostatic valve and a return temperature limiter – supplied as a compact flush-mounted unit with a white or chrome-plated cover plate.
The dual-connection manifold has six connections and is connected to the flow and return pipes of the radiator, the underfloor heating and the heating system (primary circuit). The return flow temperature limiter ensures that the fluid temperature is optimally adjusted for the underfloor heating. This means that both the radiator and the underfloor heating can be supplied simultaneously via the same circuit.
Solution for larger renovation areas: HERZ COMPACTFLOOR
When, as part of a renovation, larger areas such as individual flats are converted to underfloor heating or additional residential units are built from scratch with underfloor heating, the following situation often arises: the existing heating system continues to operate with a high-temperature circuit, whilst the newly installed underfloor heating systems require significantly lower system temperatures.
For precisely such applications, HERZ COMPACTFLOOR offers a technically clean solution for integrating multiple underfloor heating circuits into existing high-temperature systems. HERZ COMPACTFLOOR is a ready-to-connect control unit comprising a high-efficiency circulation pump and a flush-mounted box for connecting between three and twelve underfloor heating circuits. Depending on the model, variants with additional radiator outlets are also available.
The prefabricated control unit combines numerous components in a compact form, such as a manifold, flow indicators, thermostatic valves, venting, drainage, a pump, mechanical temperature control, electrical components and actuators. This significantly reduces the amount of installation and commissioning work required on site and allows different heat distribution systems to be operated reliably within a single system.
© 2026. HERZ
