ᐅ Photovoltaic panels on the roof as a second layer

Hello,

for photovoltaic systems installed afterwards, it is clear that they are simply mounted on the roofs, but why is it done this way for new buildings as well? It would be simpler and probably cheaper if a basic metal tray were installed under the solar panels.

What speaks against this?

Regards, dieter_m

There is a partial solution called in-roof installation. As is often the case, experts seem divided on whether in-roof or on-roof installation is preferable. To me, on-roof installation seems more practical.

Good luck

K1300S

In-roof installation is treated differently for tax purposes (it is no longer considered independent but part of the house, so input tax deduction is not possible).

Additionally, the modules are not installed seamlessly everywhere, resulting in transition points that can compromise airtightness.

Finally, in case of damage, you are heavily dependent on the manufacturer – with on-roof installation, you can easily replace modules yourself.

The components also get warm, so in my opinion, an on-roof installation with some ventilation behind makes more sense.

Sebastian79 schrieb:
In-roof systems are also treated differently for tax purposes (they are no longer considered separate but part of the house, so input tax deduction is not allowed).

Additionally, the modules are not installed continuously everywhere, meaning you have transition areas that can compromise airtightness.

And finally, you are very dependent on the manufacturer in case of damage—on-roof systems allow you to easily replace modules.

Another potential risk: If replacement is necessary due to damage, the standard size from 10 years ago might no longer be available. Then you have a hole in the roof that you must first seal again.

One more point regarding damage/replacement: It is not necessarily the case that your photovoltaic company will bring a new module and replace it immediately. Especially regarding warranty, dismantling and reassembly with repair is possible. During this time, your roof might remain open or only be covered with a tarp.

Bauexperte schrieb:
The panels also get warm, so in my opinion, installing them on the roof with some ventilation behind makes more sense.




Bauexperte

We have installed the panels on the roof.

Yes – unfortunately, the cells get very warm, which reduces their efficiency (a frustration for every photovoltaic system owner).

I notice a significant difference (more than 10 centimeters (4 inches) lower temperature) in the attic when the sun is shining (in the attic area, we have a cold roof with insulation in the upper floor ceiling).

Since the installation of the panels, it has been noticeably cooler up there when the sun is beating down on the roof. This obviously also benefits the temperatures in the upper floor.

Best regards,
Thorsten