Solar roof and in-roof solar systemThe roof that makes power.

A solar roof replaces the tiles with solar modules. The modules are not placed on top of the roof, but set into the roof surface. They protect the house from rain and generate power at the same time. Specialists speak of an in-roof solar system or in-roof photovoltaics.

This makes the most sense for new builds and roof renovations. You need a new roof skin anyway. The modules take over this task, and you save the tiles.

What is the difference between in-roof and on-roof?

With an on-roof system, the modules lie on a mounting structure above the existing tiles. This is the most common solution. It is quick to install and suits almost any pitched roof in good condition.

With an in-roof system, the modules lie in the plane of the roof surface. Together with flashings and seals, they form the water-bearing layer.

	On-roof	In-roof
Tiles	stay in place	omitted under the modules
Look	modules stand slightly above the roof	flush, calm surface
Suitability	existing roof in good condition	new build, roof renovation
Cost per kWp	lower	higher, but tile costs are saved
Ventilation behind modules	good	poorer, slightly lower yield
Historic core zone and protected townscape	sometimes difficult	often more likely to be approved

Both systems produce power from the same sunlight. The choice depends on your roof, your budget and the look.

Is a solar roof worthwhile for a new build?

For a new build, the timing is good. The roof is not yet covered, and we can coordinate modules, roof structure and electrical planning from the start. This saves interfaces and scaffolding costs.

It is important that the architect, roofer, sheet-metal worker and we sit down together early. Then the roof structure, connections and schedule fit. Later changes are more complex with in-roof systems than with on-roof.

And for a roof renovation?

If your roof has to be re-covered anyway, the comparison is worthwhile. With an in-roof system, you only pay for new tiles where there are no modules. You can renew the insulation and underlay membrane at the same time.

If your roof is still good, it is better not to renovate just for the solar system. Then on-roof is the cheaper solution. We tell you that during the site visit as it is.

Solar roof in a historic core zone and protected townscape

In historic core zones and for protected buildings, stricter rules apply. On-roof systems with a visible mounting structure are more likely to meet resistance there. A flush-set, uniformly black in-roof system blends in better. Sometimes solar tiles are also an option, which look closer to a tiled roof.

Approval is decided case by case. The commune and, where applicable, the heritage protection authority decide. We clarify what is possible for your address, prepare the documents and submit them.

Which roofs are suitable?

In-roof systems are made for pitched roofs. What matters are the pitch, the roof shape and the construction:

• Pitch: Every system has an approved minimum pitch. Very flat roofs are not suitable. For flat roofs, a system on stands is the better solution.
• Roof shape: Simple gable and monopitch roofs without many openings are ideal. Dormers, roof windows and chimneys are possible, but need more connection work.
• Orientation: South, east and west produce power. Where the modules go is determined by the roof surface. Unlike with on-roof, modules cannot be moved freely.
• Substructure: Rafters, battens and insulation have to suit the system. We check this with the roofer.

You continue to cover unused roof areas with tiles. So that the surface looks uniform, modules and tiles are matched in colour.

How watertight is an in-roof system?

This is the most common question, and it is a fair one. An in-roof system is watertight if three things are right:

• The system is tested and approved for the roof pitch. Very flat roofs are not suitable.
• The connections are properly executed: eaves, ridge, side edges, chimneys and roof windows need suitable flashings and seals.
• An underlay membrane lies underneath, which drains water if anything ever gets through.

This is craftsmanship that is not done on the side. We plan the system with the roofer and the sheet-metal worker so that system and roof form a whole.

And fire protection and ventilation?

Two points that are often asked about with in-roof systems:

• Ventilation: Modules become slightly less efficient in heat. On-roof modules have air underneath, in-roof modules less. Good systems therefore provide an air channel under the modules. The yield loss then stays small.
• Fire protection: The roof skin must meet the requirements of the cantonal fire protection regulations. We only choose systems that are tested for this, and clarify open points in advance with you and the commune.

What does an in-roof solar system cost?

The price depends on size, roof shape, system and effort. As a rule of thumb: per kWp, in-roof costs more than on-roof. On the other hand, the tiles and part of the roofer’s effort are omitted. If you are renovating or building new anyway, it is better to compare the additional cost compared with a tiled roof than the full price of the system.

A flat figure would not be serious, because prices vary widely depending on system and roof. You receive your exact price after the site visit in the binding quote within 72 hours. On request, we calculate on-roof and in-roof side by side, with yield, subsidies and payback.

How much power does a solar roof produce?

The principle is the same as for any system: orientation, tilt and location determine the yield. A south-facing roof produces the most, east and west a little less, but the power is spread across the day. Compared with an on-roof system, the yield of in-roof is usually slightly lower, see above. In the quote, we show you the yield forecast for your roof so that you can compare.

The more of the power you use yourself, the better the solar roof pays off. With a heat pump or an EV charger, self-consumption rises.

Subsidies

The federal Pronovo one-off payment (Einmalvergütung, EIV) is available for on-roof and in-roof systems. How much it is in your case, you see in the quote. Many cantons and communes pay additional amounts. On request, we pre-finance the subsidy.

How your project works

1. Enquiry: Online in a minute or by phone.
2. Site visit: We check the roof, roof structure, electrical installation and consumption. Free of charge.
3. Quote in 72 hours: binding, on request with on-roof and in-roof compared.
4. Permit and grid operator: We clarify the notification or building application and register the system.
5. Installation: Our own installers, coordinated with the roofer and sheet-metal worker.
6. Commissioning and handover: We show you the system and the app.

Planning through to commissioning comes from one provider. You can find more about the system as a whole under solar system and photovoltaics. How the modules themselves are built is described under PV modules. With battery storage and an EV charger, you use more of your own rooftop power.

Solar roofs in your region

Our locations are in Zumikon ZH and Lachen SZ. We build in-roof systems throughout German-speaking Switzerland. Enter your postcode in the appointment card, and we will arrange the free site visit.