Roof · Installation · Connections

Sunmaxx PVT modules can be installed on almost any structurally sound roof with a load-bearing capacity of at least 20 kg/m². Naturally, it is advantageous if the selected roof area receives several hours of sunlight per day and is not significantly shaded.

Roofs with a south-facing or east-west orientation are ideal. However, north-facing roofs can also be equipped with PVT modules if required. In this case, the system will not operate quite as efficiently and may need to be dimensioned slightly larger.

There are no specific requirements regarding the shape of the roof for installing a PVT system. Gable roofs, pyramid roofs, hip roofs, trapezoidal roofs, flat roofs, ground-mounted systems, and even façades – Sunmaxx systems have already been installed for almost every type of application.
Naturally, a roof with a largely uniform surface and few obstructions (e.g. skylights or dormers) is advantageous, as this reduces installation effort.

No, roof orientation is not as critical for PVT as it is for conventional PV systems. PVT is not solely an electricity generator; it primarily serves as a heat source for a brine-to-water heat pump. The system uses both solar energy and ambient air as heat sources.

A south-facing orientation is advantageous because higher levels of solar irradiation enable higher source inlet temperatures. However, a south-facing orientation is not a prerequisite for using PVT.

As with conventional PV systems, PVT modules are preferably installed on the south-facing side, or alternatively in an east-west configuration.
However, PVT modules use not only solar radiation to generate electricity and heat, but also the ambient air. As we know, ambient air is available from all directions. This means that a PVT system can also be installed on the north-facing side. It simply will not operate quite as efficiently as a south-facing system and may need to be dimensioned slightly larger.

Good to know: Global solar radiation – the shortwave solar radiation reaching a horizontal surface at the Earth’s surface – is also present on the north-facing side. Depending on the size of the PVT system, it may therefore be advisable to install a few additional modules for a north-facing installation in order to achieve a sufficiently high seasonal performance factor (SPF).

The type and condition of the roof coverings are generally not a limiting factor for Sunmaxx. Our modules can be installed on almost any type of roofing system – the only requirement is sufficient ventilation behind the heat exchanger on the rear of the module. With our system, a 40 mm clearance between the modules and the roof covering is standard.
Since Sunmaxx modules are typically designed to operate for 20 years or more, the condition of the roof should be assessed before installation and, if necessary, the roof should be renovated beforehand.

Our system requires a minimum clearance of 40 mm between the roof covering and the back of the module. This ensures, firstly, sufficient air circulation and convective heat transfer at the rear of the module and, secondly, provides enough space for the piping and the supply line that carries the heat-transfer fluid to the heat exchanger.

Good to know: Combined PV and PVT systems are also possible. Unlike many other PVT modules, Sunmaxx modules are compatible with all common PV mounting systems.

The durability of our modules has been tested with hailstones measuring 35 mm in diameter, and they have been certified with Hail Resistance Class 3. As with conventional PV modules, we use 3.2 mm thick safety glass.

On pitched roofs, trapezoidal sheet metal roofs, and ground-mounted systems, our modules can be installed in either orientation. For flat roofs, the standard hydraulic configuration is a horizontal layout (so-called landscape orientation) in an east-west configuration. This allows for maximum use of the available roof area while minimizing installation effort and wind loads.
When mounting the modules on the substructure, the position of the hydraulic connections must be taken into account. The mounting rails must not cover the connections or pinch the hoses.

For flat roofs, we recommend an east-west orientation. The tilt angle is typically 10° to 15°. However, PVT systems on flat roofs have also been successfully installed with a 0° tilt angle already.

Under certain conditions, a Sunmaxx PVT system can also be installed with a 0° tilt angle. In this configuration, the PVT system would not be visible from below the building. Such a configuration is typically chosen for purely aesthetic reasons.

A Sunmaxx PVT module weighs less than 30 kg when filled. Compared to other PVT modules, our system is exceptionally lightweight. A flat-roof system, including the filled modules, piping, and mounting structure, weighs approximately 18-19 kg per m² of PVT area.
However, the height of the building must also be taken into account, as wind loads need to be factored into the calculation. With a remaining load-bearing capacity of at least 20 kg per m², a flat-roof system with Sunmaxx modules can generally be installed without concern. Nevertheless, for individual projects, we recommend consulting a structural engineer.

n east-west mounting configuration allows for more efficient use of the available roof area. This is due to the alternating arrangement of the modules, which enables up to 40% more solar modules to be installed on a flat roof compared to a south-facing configuration.
At the same time, east-west systems offer significantly less exposure to wind and can be installed with less ballast. This makes it possible to install many PV and PVT systems on flat roofs that would otherwise not have sufficient load-bearing capacity. Roof penetration is not required.

Currently, in-roof PVT systems are not possible, either with Sunmaxx or with modules from other manufacturers. The reason is that the convective heat gains require adequate ventilation behind the modules.
PVT modules generate heat not only from solar radiation but also from the ambient temperature. The ambient air therefore remains a heat source even when the sun is not shining – for example, in winter, on cloudy days, or at night. For this reason, PVT applications generally require consistent rear ventilation of the modules.

Good to know: While in-roof systems are visually appealing, they also have certain disadvantages. For example, the roof space behind conventional PV modules can become very hot.

Yes. Numerous façade systems have already been implemented using our modules. From a purely technical perspective, there are no concerns about using Sunmaxx PVT modules on façades: the solution is energetically beneficial, technically feasible, and poses no particular challenges in terms of mounting. The systems operate just as reliably as conventional rooftop installations.

The only factors that need to be considered are the location of the façade and whether people could be present underneath the installation. Specific regulations may apply to buildings adjacent to public pathways or roads. A building code assessment may therefore be required before purchasing the system. For example, PV systems are subject to regulations governing vertical glazing, which consequently also apply to PVT systems.

For covered traffic routes, a general technical approval (Allgemeine bauaufsichtliche Zulassung, abZ) is required in Germany. We do not currently have such an approval, as the certification process involves considerable effort and covered traffic routes represent a very niche application for PVT.
Since the dimensions of the modules and mounting structure also play a decisive role, a new certification would generally be required whenever the product is modified. At this stage, this is not economically viable for Sunmaxx. We are also not aware of any other PVT systems or manufacturers that currently have such an approval.

Façade systems, on the other hand, have already been implemented several times using our modules, including PVT walls and fences. There is currently no certification requirement whose absence would prohibit installation. Together with our partner GES Gebäude-Energiesysteme GmbH(opens in new tab), we are working on a suitable standardized solution.

Sunmaxx works with numerous installation companies, which you can find in the partner section(opens in new tab) of our website. These companies have been trained in our PVT technology and can provide expert advice and support.
In many cases, these are companies that combine heating and solar installation expertise under one roof or work together as part of a partner network. We also work with roofing companies that employ heating specialists within their organization.
In general, both heating and solar installation expertise are required to install a PVT system: a heating contractor (HVAC installer) and a solar installer/electrician.

PVT installation is slightly more complex than installing a conventional PV system. On the one hand, the system must be electrically connected to the building; on the other, it must be integrated into the hydraulic circuit.

However, Sunmaxx modules are exceptionally easy to install. Thanks to the innovative heat exchanger technology with a fully enclosed rear side, the additional installation effort compared to conventional PV is only minimal.

This depends on the type of PVT modules being used. For Sunmaxx, the answer is yes: our modules are compatible with all common PV mounting systems.
At just 7 kg heavier, our modules are only slightly heavier than conventional PV modules. A Sunmaxx module covers approximately 2 m², which means an additional total load of only 3.5 kg per m². In other words, a Sunmaxx PVT system weighs just 3.5 kg more per m² than a conventional PV system. This difference is marginal and, in the projects known to us, has not required any different mounting design.
For existing roofs, however, we always recommend checking the permissible load-bearing capacity in advance and, if necessary, carrying out a roof renovation before installation.

Sunmaxx uses 40 mm module frames and standardized module clamps. Our system is compatible with all common PV mounting systems, giving installers a wide range of options.
Due to its ease of installation, we particularly recommend the Tric mounting system from Sunmaxx wholesaler Wagner Solar(opens in new tab), which also offers customized solutions for green roofs and complex roof geometries.

Sunmaxx uses flexible hoses with hydraulic push-fit connectors developed in collaboration with an experienced quality manufacturer. The connection is based on a tongue-and-groove system and has been used successfully in outdoor applications for many years.

Each of our PVT modules is supplied with two connection hoses. They are tested for maximum mechanical stress and provide excellent leak tightness.

Power optimizers or microinverters at the module level were commonly used in the past. However, individual optimizers generally do not provide sufficient additional energy yield to outweigh the disadvantages of adding another electrical component. The trend is therefore increasingly towards high-quality inverters.
That said, Sunmaxx modules can be combined with microinverters without any issues.

On the electrical side, a PVT module behaves like a conventional PV module. Therefore, the same inverter manufacturers are available as for standard PV systems.

Traditional solar thermal systems were often designed with copper piping. However, copper piping is not compatible with Sunmaxx systems and cannot be reused.
The reason is straightforward: to keep costs and the additional weight of our modules as low as possible, we use aluminium on the thermal side. Aluminium is not compatible with copper. An improper combination of the two materials can lead to corrosion of the modules.
We therefore always recommend using stainless steel or plastic piping for the hydraulic circuit.

For a PVT system with plastic piping, no additional fittings are required. When using stainless steel piping, a special adapter is used. It features a 14 mm push-fit connection on one side and a 15 mm compression fitting on the other. For installation, a 15 mm stainless steel smooth pipe is therefore sufficient. The adapter can then be fitted directly onto the pipe.

Our connection hose technology is based on a tongue-and-groove connection system. The push-fit connectors are equipped with safety rings. By pulling the safety rings back, the hoses can be disconnected at any time if required.

The absorber can generally be rotated in any direction. There is no distinction between the supply and return connections on the module, meaning that the module can also be rotated without affecting its functionality. There is likewise no technical disadvantage to installing the modules horizontally rather than vertically.

Important to know: Sunmaxx PVT systems are closed-loop systems and must be properly vented during installation.

No. A PVT system should not be installed as a DIY project. Proper installation, connection, and commissioning require both a heating contractor and a solar installer/electrician.

Please feel free to contact us even if there is currently no installer for your region listed on our partner map(opens in new tab). We work closely with heat pump manufacturers that have their own installer networks, so we can usually connect you with a suitable installation partner.

It is estimated that an existing building is fitted with a PV system every day. This has become standard practice, and the same applies to PVT. In fact, most PVT projects involve existing buildings where an outdated oil or gas heating system is replaced with a fully renewable heating system consisting of Sunmaxx PVT and a brine-to-water heat pump. So, yes: PVT can be retrofitted without any problems and is not limited to new-build projects. The only important requirement is that the roof has sufficient load-bearing capacity. The additional load of a Sunmaxx PVT system compared to conventional PV is just 4–5 kg/m². Once installed, a PVT system operates highly efficiently and reliably, with a service life of at least 30 years.