FAQs

KERMI sells its products exclusively via a three-tier distribution system. This means that

• KERMI supplies specialist wholesalers.
• The wholesaler supplies the specialist partner.
• The specialist partner plans, sells and installs the products for the end customer.

This ensures that you as a customer receive professional advice, planning and installation - directly from trained and qualified specialist companies. We do not sell directly to end customers.

Specialist partners can use special online forms on the website to report a service case, request an initial operation or ask technical questions (e.g. about the heat pump or residental ventilation). Alternatively, a service number is available.

With the KERMI specialist partner search , you can quickly and easily find qualified installers in your area.

Our authorised specialist partners are on hand to provide you with professional advice, careful planning and expert installation.

Yes, as a private customer you can order spare parts directly from the Kermi spare parts shop. There you will find a large selection of original parts for radiators, heating systems and ventilation technology. You also have the option of ordering spare parts from your specialist partner or installer if you need support with selection or installation.

The download centre is available to all users without registration. You can freely access installation instructions, brochures, technical data sheets and other documents at any time.

KERMI offers a comprehensive download centre where you can find all important documents at a glance.

Whether installation and operating instructions, brochures and technical data sheets - the right documents are conveniently available in PDF format for all product areas.

Yes, it often makes sense to replace old radiators. Outdated models often work inefficiently. They consume more energy and no longer provide the desired level of heating comfort. By replacing your radiators, you can significantly increase the efficiency of your heating system, save costs and improve your quality of living.

In principle, replacement is possible without any problems. However, classic (flat) radiators usually have a side connection, which is why some towel radiators are more practical for this than others. Special renovation solutions such as the KERMI Basic-D, Casteo-D and Duett-D models are the most suitable for replacement.

First of all, the required heat output must be right. This depends on the size of the radiator. The connections must also be taken into account. The least effort is required here if existing connections can be used again. Purely electric radiators, which only require a socket for the connection, have also proven to be a good alternative, especially for localised heating requirements.

It is important that the heating surface is large enough to achieve the required heating capacity. If space is limited, it may be worth reducing the installation distance of the pipes or installing panel heating in the wall. It is also important to bear in mind when switching from radiators to underfloor heating: Radiators are usually operated with higher flow temperatures than underfloor heating systems. An adjustment should therefore be made here if necessary, as temperatures that are too high with underfloor heating are perceived as uncomfortable.

Yes, this is possible without any problems! Modern heat pump radiators such as our X-Flair are specially designed to work efficiently with the low flow temperatures of a heat pump. Thanks to integrated fan technology, the heat is optimally manifolded in the room, resulting in fast and even heating. This allows you to enjoy a pleasant indoor climate and benefit from an energy-efficient heating system at the same time.

Choosing the right radiator depends on various factors, such as the size of the room, the desired heating capacity and the heating system. Our guide will help you find the ideal radiator for your needs - whether for a new build or modernisation.

Yes, with our upgrade sets you can give your old steel panel radiators a modern and stylish look in no time at all. The covers are manufactured to fit perfectly, can be fitted without drilling or screws and provide a quick and easy upgrade to your interior design. Thanks to the robust metal, they are durable and offer excellent thermal conductivity - a clear advantage over wooden or plastic panelling.

Hydraulic balancing ensures that each radiator in a building receives exactly the quantity of heating water it needs to heat the respective room efficiently and evenly. The first step is to calculate the heating load for each room, i.e. the amount of heat required to reach the desired temperature. Factors such as room size, insulation, number of windows and outside temperature are included in this calculation. Based on the heating load, the optimum water volume required by each radiator is then determined in order to avoid over- or undersupply. The pre-settable thermostatic valves are then adjusted so that they let through exactly this calculated water volume. If necessary, the heating pump is adjusted or replaced with an energy-efficient high-efficiency pump to optimise the water pressure in the system and reduce energy consumption. In addition, hydraulic balancing can often lower the flow temperature of the heating system, which enables further energy savings. Without hydraulic balancing, the heating water usually flows along the path of least resistance, which means that radiators close to the pump are oversupplied and radiators further away are insufficiently heated. This leads to uneven heat distribution, unpleasant flow noise, overheated or cold rooms and increased energy consumption. Hydraulic balancing distributes the water flow according to demand, resulting in even heat distribution, improved living comfort, reduced noise and lower heating costs. In addition, it is often possible to receive subsidies for this measure. Overall, hydraulic balancing ensures efficient, comfortable and environmentally friendly heating.

A floor stand bracket for radiators is a specially developed bracket that allows the radiator to be fixed directly to the floor rather than to the wall and positioned free-standing. This is particularly practical in situations where wall mounting is not possible or not desired, for example in listed buildings, floor-to-ceiling windows or special room design requirements. The floor bracket provides a stable base and secure footing for the radiator, while at the same time offering more flexibility when positioning it in the room. Floor brackets specially developed for KERMI convectors consist of a base plate and a matching cover, which are designed like half-panels. This creates a hollow space in the centre in which connection pipes can be routed inconspicuously from the floor to the radiator. In addition, an opening in the base plate allows the installation of a thermostatic sensor head without the pipes being visible. Floor brackets thus combine functionality, stability and an attractive design that blends harmoniously into the room.

The requirement class for radiators describes the loads that a radiator must be able to withstand at its place of use. It relates primarily to the fixing, stability and safety & security of the radiator and takes into account the various physical impacts that can occur in everyday life - from harmless support, sitting or climbing to high loads caused by crowds in special situations. Originally, there were four requirement classes, of which requirement class one was cancelled with the last directive, as it was almost never used in practice. It comprised typical residential and office areas in which no particular stresses are to be expected. Today, there are still three requirement classes, ranging from normal to very high requirements. The first class valid today (requirement class two) applies to publicly accessible areas such as sales rooms or stairwells where the radiator may occasionally be used carelessly. The third requirement class is aimed at places with high requirements, such as classrooms or escape routes, where radiators also serve as seating or must remain stable in panic situations. The fourth class is for very high requirements and special loads, such as those found in prisons or psychiatric facilities, and requires particularly robust fixing. The categorisation into requirement classes ensures that radiators are mounted safely and stably according to their environment in order to prevent damage and hazards caused by loads.

As a rule, modern radiators already provide pleasant warmth in the home at low flow temperatures, as is typical for heat pumps. Modern radiators have a larger surface area, which enables a more even and better heat distribution. However, heat pump radiators are particularly efficient when operating at low flow temperatures. These are specially developed to ensure optimum heat dissipation even at lower temperatures. Heat pump radiators have integrated fans (blowers) that distribute the warm air more quickly in the room. These fans significantly increase convection, which more than doubles the air turnover and transfers heat much faster and more efficiently in the room. This efficient heat transfer results in high energy efficiency, a pleasant indoor climate and lower operating costs. One example of such a radiator is the x-flair heat pump steel panel radiators from KERMI. It combines the proven x2 technology with an integrated, fully automatic axial fan system that ensures rapid heating and effective heat distribution. The fans switch on and off as required and operate particularly quietly. The x-flair is ready to plug in and is suitable for both new builds and refurbishments. It also offers flexible connection possibilities and matches the look of other radiator versions from KERMI. This makes it ideal for the requirements of low flow temperatures.

The KERMI therm-x2 Vplus steel panel radiators will be discontinued at the end of 2025. It will be replaced by the new KERMI therm-x2 Vmulti steel panel radiators. The Vmulti combines all connection versions of the previous Vplus versions in one model and also offers the option of swapping the valve from right to left. With six different connection possibilities, the Vmulti allows a high degree of flexibility, even when changing the type of connection on site at short notice, and full design freedom with maximum availability. The size and colour range remains identical to the previous Vplus product variety. This changeover applies equally to the respective x-flair version, meaning that the x-flair Vplus will be replaced by the x-flair Vmulti at the end of 2025, meaning that the extended connection possibilities and increased flexibility of the new model will also be available here.

Steel radiators can rust if the material comes into contact with air and water. As a rule, radiators are therefore coated with a priming and paint layer to prevent the penetration of moisture and oxygen. However, if the radiators are exposed to increased moisture in their range of applications, e.g. next to the bathtub or walk-in shower cubicles, KERMI also offers a special anti-corrosion coating. It is applied directly to the KERMI radiator and then finished with a high-quality powder coating. The paintwork can be applied in any desired shade.

For areas with particularly high anti-corrosion requirements, such as swimming pools, industrial plants or rooms that are regularly wet-cleaned, selected KERMI radiators are also available in a galvanised version. The hot-dip galvanising forms a resistant zinc coating that ensures optimum protection against rust even in damp or aggressive conditions.

Window open detection is a function of heating or radiator controls that recognises the opening of a window and then temporarily lowers the setpoint temperature in the affected room by activating the antifreeze protection function. In this way, unnecessary heating with open windows can be avoided in order to save energy. If the window is closed, the system recognises the temperature increase and returns to the last set operating mode. Alternatively, the antifreeze protection function can also be cancelled manually by pressing a button. For window open detection, the control unit records various parameters such as the temperature setting, room temperature fluctuations, outdoor temperature and the installation location of the device.

Regular cleaning of the radiators is generally recommended. This prevents the accumulation of dust and dirt, which can impair heat output. Special radiator brushes, a hoover with a narrow attachment or a hairdryer are suitable for removing dust and loose dirt in hard-to-reach areas. Cleaning agents can be used for stubborn dirt. However, it is important to ensure that the agents used are not too aggressive in order to avoid damaging the radiator. For example, only mild, non-corrosive and non-abrasive cleaning agents and soft cleaning textiles should be used for painted surfaces, such as the KERMI therm-x2 steel panel radiators. The same applies to convectors and heating panels.

If a radiator is installed in front of cold window surfaces or on poorly insulated walls, a radiation shield can be installed behind the radiator. This prevents the heat energy from being lost on the cold surfaces and instead returns the heat to the room by radiation. With the KERMI radiation shield, up to 80 % of heat loss can be avoided. The size of the radiation shield depends on the size of the radiator and is available in the entire KERMI colour spectrum, so that the radiator and radiation shield are a perfect visual match.

The KERMI radiation shield has a flat front and is supplied complete with fastening elements, making it easy to install directly on the steel panel radiators.

A special version with an integrated radiation shield is available for Kermi convectors.

Yes, the replacement of a conventional standard radiator with the KERMI x-flair heat pump radiator is possible without any problems. As the lug positions are identical for both radiator types, the existing brackets can continue to be used in most cases. The existing connections can also generally be used 1:1. In addition, the x-flair only requires a power connection for the integrated fan system. This means that after converting the heating system to a heat pump, suitable x-flair radiators that are optimised for low flow temperatures can be installed easily and without major conversion work.

The KERMI E-Panel is operated via a control unit with a function display attached to the side of the radiator and offers three standard operating modes: comfort mode, eco mode, and antifreeze protection.

In comfort mode, the preset target temperature (e.g. 19 °C) is maintained around the clock and can be adjusted by the user. Eco mode automatically lowers the temperature by 3.5 °C compared to comfort mode, ideal for night-time reduction or short-term absence (2 to 24 hours). For longer absences (more than 5 days), the antifreeze protection function should be activated. It maintains a minimum temperature of 7 °C to prevent frost damage.

Most KERMI design radiators and therm-x2 steel panel radiators are suitable for the installation of heat cost allocators or evaporation meters. The exact position and coupling factors depend on the specifications of the respective manufacturer of the recording devices and may vary. For correct installation, it is advisable to contact the installation service or the manufacturer of the heating cost recording device.

Please note for KERMI therm-x2: The serial flow achieves a higher average surface temperature. For types 12, 20, 22, 30 and 33, this may require repositioning of the heat cost allocators in order to record consumption correctly.

A bench can only be constructed using a frame bracket, as this provides the necessary stability and loading capacity to safely support the weight of the bench and the people sitting on it. Frame brackets are particularly robust fixings for KERMI convectors. They can be used either as soil stand brackets under the convector or additionally above the convector as a base frame for a bench. To create a stable and load-bearing structure for the installation of the bench, both consoles are connected with long threaded rods.

KERMI's patented x2 technology is based on the serial flow through multi-layer flat steel panel radiators, whereby the front panel is first flowed through by the warm flow water before the rear panels follow.

In normal operation, heating the front panel is sufficient: the heat is thus transferred directly to the room via the front panel. This ensures up to 100% higher radiation component and a pleasant indoor climate. When the heat demand increases, the rear panels are also activated, contributing to rapid room heating with high convection output. This results in heating periods that are up to 25% shorter.

Overall, the targeted water flow of x2 technology results in a shorter heating cycle, shorter operating times and the factory-preset kv valve closes more quickly. This enables energy saving of up to 11%.

All multi-layer KERMI flat radiators are equipped with x2 technology as standard. Exceptions are single-layer steel panel radiators (as they only have one panel) and KERMI E-Panel radiators, which are exclusively electric and therefore operate without water flow.

Originally, a special KERMI x2 clip was used for the market launch of serial flow-through technology in order to make the x2 technology visible. Since all multi-layer flat steel panel radiators are now equipped with this technology as standard, separate labelling on the clip is no longer necessary.

Single-layer steel panel radiators and the KERMI E-Panel electric models, which operate without water flow, are excluded from x2 technology.

Dry cooling means that rooms are cooled without condensation forming. Cold water is generated in the heat pump by reversing the refrigerant cycle. This water is fed through special heat pump radiators that have integrated fans. The cold water extracts heat from the room via the heating or cooling surface of the radiator, while the fan distributes the cool air evenly without creating condensation. At KERMI, this form of cooling is possible with the x-flair heat pump radiator, which requires a thermostatic sensor head with K setting from the KERMI product range.

Noise emissions are generated during operation of the x-flair heat pump radiator by its integrated fans. However, these operate very quietly at a noise level of only around 28.5 decibels. Thanks to the combination of sound-optimised fans and integrated sound decoupling, the x-flair is quieter than a whisper and therefore barely audible, even when heat demands fluctuate.

A support bracket is required if the wall material is not strong enough to safely support the weight of the radiator. Since the load-bearing capacity of the mounting brackets depends directly on the strength of the wall material, the load-bearing capacity may be reduced, especially in the case of heat-insulating wall materials with cavities. In such cases, in addition to the wall bracket, a support bracket is mounted on the floor under the radiator to absorb most of the weight. The wall brackets on the upper fixing lugs mainly absorb the forces in the horizontal direction (towards or away from the wall), thus ensuring high stability. This type of installation can therefore be particularly advantageous for vertical radiators.

KERMI fixing brackets are designed for high load-bearing capacity and stability. However, in ensuring safe installation, the building material of the wall to which the radiator is attached also plays a decisive role. In this respect, the stability of the brackets is basically proportional to the strength of the wall material – the stronger the building material, the higher the load-bearing capacity of the brackets.

This is particularly important to note in the case of modern, heat-insulating wall materials, which often have a hollow structure to achieve an insulating effect. However, this reduces their load-bearing capacity. With such walls, point fixing, such as with built-into-wall brackets, is often insufficient, as the weight of the radiator is only distributed over a few points. In these cases, it makes more sense to use fixing solutions such as wall rails or soil stand brackets, which distribute the weight better and thus enable safe and stable installation.

The main difference lies in the way the mounted radiator is secured: with a long wall bracket, once the radiator has been hooked into the bracket, it is secured against being lifted out in a further step using a safety clip. The quick mounting bracket, equipped with a spring mechanism, enables quick fixing and securing of KERMI flat radiators.

It's very simple: after the bracket is installed on the wall, the spring tension is applied. The radiator is then hooked into the holder with the lower tab and pressed against the tensioned spring with the upper tab. This securely locks the radiator in place and protects it from being lifted or moved – without any further installation steps.

The cable for the KERMI E-Panel electric flat radiator is located on the right-hand side and is 80 cm long.

KERMI offers a diverse portfolio of mounting solutions for wall and floor mount that can be adapted to various installation conditions. These include wall brackets for stable wall mounting with fixed or individually adjustable distance, quick mounting brackets with integrated dehinging safety device for fast installation, and internal and external soil stand brackets, which are particularly useful for floor-to-ceiling windows or difficult wall conditions.

All KERMI flat radiators have identical bracket positions, which makes the replacement of the radiators easy and straightforward. This means, for example, that a KERMI standard radiator can be easily replaced with a heat pump radiator such as the x-flair from KERMI after modernisation with a heat pump. All fixings comply with the requirements of VDI 6036.

A selection of towel rails is available for all KERMI flat panel radiators. The only exception is the x-flair heat pump radiator, which cannot be fitted with a towel rail due to the axial fans integrated under the top cover.

For all vertical flat panel steel panel radiators (Verteo series), it is also possible to install several towel rails one above the other. Alternatively, a window sill with storage space can be installed instead of a towel rail on horizontal flat panel steel panel radiators.

Towel rails can be retrofitted to almost all KERMI steel panel radiators. The only exception is the x-flair heat pump radiator, where the axial fans integrated under the top cover make it impossible to fit rails. A selection of suitable towel rails is available for all other horizontal and vertical steel panel radiators, with different lengths available for horizontal models.

The number of towel rails that can be mounted on a KERMI radiator depends on the design and length of the radiator: With the vertical Verteo radiator, however, it is possible to mount several rails one above the other. However, care should be taken to ensure that the upper rails are still easily accessible, the lower rails have a sufficient distance from the floor, and there is enough space between the rails for practical use.

The number of brackets required for KERMI radiators depends on the loads acting on the fixing system. The main factors here are the weight of the radiator, the heating medium and any attaching. At the same time, additional loads during use also play a role, for example when people sit on the radiator, lean on it or place objects on it. The properties of the wall material must also be taken into account.

In general, the following applies: if the material has a lower load-bearing capacity or the load is higher, a larger number or special selection of brackets may be necessary. The selection and quantity always depend on the specific installation conditions on site and the respective loads.

All fixings included in the scope of delivery of the radiator comply with the requirements of VDI 6036, requirement class II. Brackets in accordance with VDI 6036 in requirement classes II and III are available in the comprehensive accessories range.

The NT 2000 V compact radiator is a compact radiator with an integrated valve fitting, which KERMI launched on the market as an innovation in 1987: the integrated valve made the installation of the radiator much easier. Today, the NT 2000 is no longer sold in this form. Instead, KERMI's modern, energy-saving steel panel radiators are also available in a valve version. As with the NT 2000, the valve insert with preset kv values is already integrated ex works.

The valve fitting is already integrated into the NT 2000 V compact radiator, so no additional valve insert is required during installation. However, if the valve insert needs to be replaced during maintenance or repair, service valve inserts are available. As the model was introduced in 1987 and is no longer available, the appropriate valve insert varies depending on the production period:

• For models manufactured between 1991 and 1993: V1K Service Standard or V1K Service for low water volumes
• For models manufactured between 1994 and 2000: V2K Service Standard or V2K Service for low water volumes

To select the correct valve insert, always check the production year of the radiator.

The NT 2000 V compact radiator is an older model and differs significantly from current radiators in several respects. Today's modern KERMI steel panel radiators feature patented x2 technology as standard, which enables significantly more efficient heat dissipation through serial flow. As a result, new models heat up faster, provide more comfortable warmth and can save up to 11% energy. The NT 2000 does not yet feature this technology and therefore does not achieve the same efficiency or shorter heating times as current models. Compared to the older NT 2000 V compact radiator, modern KERMI radiators also offer a significantly wider range of sizes, front designs and colours, as well as more connection versions.

A heat pump absorbs free environmental energy from the surroundings. In a refrigerant circuit, the temperature is increased by compression and then transferred to the heating system.

The heat pump principle consisting of heat absorption, heat compression, heat transfer and expansion also works in cold winters and provides sufficient heat in the rooms. However, the more the absorbed environmental energy has to be increased, the more the refrigerant in the heat pump has to be compressed. This increases electricity consumption somewhat. However, this is usually only the case on a few days a year when temperatures fall well below 0 degrees.

A heat pump is first and foremost an environmentally friendly heating solution. But it can also be used to cool the building comfortably in summer. It extracts heat from the rooms and dissipates it to the outside. This effectively lowers the temperature inside the house. Compared to an air conditioning system, there is no draught.

Air source heat pumps generally work at all temperatures, but their efficiency decreases as the outside air temperature falls. The outdoor temperatures at which a heat pump works efficiently can be recognised by the addition of the COP value: COP 4.96 (A2/W35) means, for example, that at an outside temperature of 2 degrees and a flow temperature of 35 degrees, a very high coefficient of performance of 4.96 is achieved. This means that one kW of electricity generates 4.96 kW of heating energy.

Choosing the right heat pump depends on several factors, including

• Building type & insulation: new buildings often require less heating capacity than unrenovated old buildings.
• Heat source: Air, ground or groundwater - there are different options depending on the location and space available.
• Heating system: Underfloor heating or radiators? Heat pumps work particularly efficiently with panel heating.
• Hot water requirement: Households with higher hot water consumption require a more powerful solution.
• Funding opportunities: In many cases, there are government subsidies for installing a heat pump.

Whether air-to-water, brine / water heat pumps or water-to-water heat pumps - our guide will help you find the optimum solution for your home.

To maximise the self-consumption of your self-generated energy, e.g. from a photovoltaic system, the heat pump can be specifically integrated into the energy management system. An electricity storage unit helps to store surplus solar power and use it to operate the heat pump. In this way, you reduce the amount of electricity drawn from the grid, lower your energy costs and increase the efficiency of your heating system.

Yes, a heat pump can not only heat, but also cool. In the warm months, it extracts heat from the room and releases it into the environment. This works either via panel heating systems such as underfloor or wall heating or via special heat pump radiators. This allows you to enjoy a pleasant indoor climate all year round - efficiently and in an environmentally friendly way.

Yes, the installation of oil heating systems is still possible after 2025 under certain conditions, but different deadlines apply depending on the size of the city: In cities with more than 100,000 inhabitants, installation is permitted until 30 June 2026 at the latest, in smaller cities until 30 June 2028. A consultation regarding the economic efficiency must take place before installation in the existing building.

After 2026, oil heating systems may only be installed if they utilise a certain proportion of renewable energies, according to the provisions of the Building Energy Act (GEG).

From 2029, there will also be a gradual switch to so-called "green heating oil" - heating oil that contains a proportion of biogenic raw materials such as vegetable oils or used fats. Oil heating systems installed after mid-2026 (or 2028) must be operated with at least 65 per cent green heating oil from the outset.

In view of these requirements and, above all, for ecological reasons, it makes sense to (fully) switch to renewable energies now.

The Building Energy Act (GEG) of 2024 does not prescribe the general replacement of oil heating systems. However, replacement is mandatory for oil heating systems with an output of between 4 and 400 kW that are more than 30 years old and use constant temperature technology. The chimney sweep determines this obligation and informs the owner. There are exceptions for owners of detached and semi-detached houses who lived in the house before 1 February 2002 - the replacement obligation does not apply here. In the event of a change of ownership after this date, the new owner has two years to replace the old oil heating system. Oil heating systems that were installed before 1 January 2024 and do not fall under the replacement obligation are protected until the end of 2044 and may continue to be operated and repaired. Oil boilers with modern condensing or low-temperature technology are exempt from the replacement obligation. However, switching to renewable energies not only makes sense from an ecological point of view, but is also financially supported by various subsidy programmes.

Although a new oil heating system with modern condensing technology is more efficient than older models, it is not very sustainable in the long term. The Building Energy Act (GEG) increasingly restricts the use of fossil fuelled heating systems: Oil-only heating systems are already no longer being installed in new builds, while minimum proportions of bio heating oil will apply to existing buildings from 2029, rising to 60% by 2040. Oil heating systems will be completely banned from 2045. There are also many other reasons not to install them: oil heating systems cause higher CO₂ emissions and particulate matter, are dependent on fluctuating oil prices and rising CO₂ taxes, require space for the oil tank and are no longer subsidised. In the long term, this can have a negative impact on property value. This is why switching to renewable heating systems is usually the more sensible and sustainable choice.

The coefficient of performance of a heat pump is also called COP (coefficient of performance) and is an important indicator of efficiency. The COP value always refers to a defined operating point and describes the ratio of electrical power consumed to heat output delivered. A COP value of 4.96 (A2/W35) for an air/water heat pump means, for example, that at an air temperature of 2°C (=A2) and a flow temperature of 35°C (=W35), 1 kW of electrical energy produces 4.96 kW of heating capacity. In principle, therefore, the higher the COP value, the more efficiently the heat pump works and the less electricity it requires to operate.

Yes, heat pumps are also a sensible and environmentally friendly heating solution for old buildings. They utilise free energy from the air, water or earth, making you independent of rising oil and gas prices. However, in order for the heat pump to work efficiently in an old building, a few requirements must be met: Good insulation of the roof, façade and windows is important to minimise heat loss. It should also be checked whether the existing radiators can provide the desired level of heating comfort even with the lower temperatures of the heat pump. Replacing the old radiators with special, particularly efficient heat pump radiators may make sense here.

Heat pumps can also be operated with modern (flat) radiators without any problems. The flow temperature - i.e. the temperature to which the water is heated before it enters the heating circuit - is crucial for efficient operation. Heat pumps work particularly efficiently at low flow temperatures. For this reason, radiators should be used that bring the desired thermal comfort into the rooms at such low temperatures. Older radiators often do not achieve this and should be replaced with modern radiators. Special heat pump radiators, which are optimised to the requirements of the heat pump and thus enable maximum efficiency, are particularly effective.

The structural requirements for the installation site differ depending on the type of heat pump. Air-to-water heat pumps are the easiest to install. A stable substrate should be available for outdoor installation. Devices for indoor installation require a room, e.g. in the basement, that has load-bearing capacity and is well ventilated.

Brine / water heat pumps, on the other hand, require geothermal collectors to be laid over a large area or geothermal probes to be installed at depth. This requires either a large, unsealed area (collectors) or a soil expertise (probes). For water-to-water heat pumps, two wells must be drilled to transport the groundwater to the heat pump. As a rule, this access must be authorised.

Due to these structural preparations, brine / water heat pumps are usually more suitable for new buildings or major refurbishments, while air / water heat pumps are also suitable for retrofitting existing buildings.

Whether a permit is required depends on the type of heat pump. Air-to-water heat pumps and brine / water heat pumps with geothermal collectors generally do not require a permit, as no deep drilling into the groundwater is necessary. With air-to-water heat pumps, however, attention should be paid to the distance to the neighbouring property, as the devices can cause noise during operation.

For water-to-water heat pumps, on the other hand, a permit is required as deep drilling is required and groundwater is used. The regulations vary depending on the federal state. It is therefore important to obtain information in advance from the relevant water authority and the geological service.

A combination of heat pumps and photovoltaic systems is not only easily possible, but also makes sense. Heat pumps require electricity to operate. By combining them with photovoltaic systems, they can be operated with self-generated, green electricity in a way that conserves resources and saves costs. The x-change dynamic heat pumps from KERMI enable the intelligent use of PV electricity to generate heat on demand thanks to the built-in power-to-heat function. The heat generated is stored in a heat storage unit and is then available when needed.

Choosing the right residental ventilation system depends on various factors such as the size of the house, the number of people in the household and the desired energy efficiency. Our various ventilation models offer solutions for every need - from simple decentralised ventilation to more complex systems with heat recovery. Use our guide to find the system that best suits your home and your requirements.

You can conveniently purchase new filters for your residental ventilation system from our KERMI spare parts shop or from your specialist partner. This way, you can ensure that your ventilation system is always equipped with suitable, high-quality filters.

The filter in ventilation systems can be changed without tools and should be done approximately every 180 days – ideally, one filter change should be done in spring, after the ‘cold/wet’ season, and one in autumn, after the ‘dusty/pollen’ season. Shorter intervals may also be necessary due to the natural environment. The procedure varies depending on the type of device and is described in the device manual. However, it is important to only change the filter when the power is off, both for centralised and decentralised residential ventilation systems.

A centralised ventilation unit must therefore first be switched off or disconnected from the mains. The filter flap can then be opened and the foam stoppers removed. The outside air filters and extract air filters are then removed and new original filters are inserted. Pay attention to the direction of the arrow, which indicates the direction of flow. Then close the stoppers and flap again and switch on the unit.

For decentralised x-well pendulum fans, the filter should generally be changed every three months. The filters are located behind the inner panel. To perform a replacement or clean them, disconnect the fan from the mains, pull the inner panel out of the installation pipe and either clean the respective filter or replace it if it is heavily soiled or defective. As a general rule, dust filters should be checked every six months and pollen filters every three months.

The x-well A12 from KERMI is a small room fan for decentralised venting of individual rooms such as bathrooms, toilets, utility rooms or kitchens. It is installed directly in the outer wall and reliably transports moisture and stale air from the respective room to the outside. In this way, it helps to protect the building fabric from moisture and mould. The fan can be operated continuously, at partial or full capacity, demand-controlled or manually. Thanks to its modern EC motor and side air inlet, the x-well A12 is energy-efficient and quiet.

The decentralised x-well A12 small room fan is easy to clean by removing the cover rosette and cleaning the visible plastic parts with a soft, slightly damp cloth. Avoid using aggressive cleaning agents. Dust and light soiling in the fan area can be carefully removed with a vacuum cleaner on a low setting or a brush. In the case of heavier soiling, cleaning by a specialist partner is recommended in order to ensure the long-term functioning of the device.