Solar systems on roofs are now commonplace. However, it is not always possible to use the own roof in order to gain solar heat (solar thermal energy, ST) and / or solar energy (photovoltaic, PV) by means of free solar energy. Reasons for non-acceptance:

- the statics: because the roof does not have the necessary load bearing capacity for the solanalage and can not be post-stabilized accordingly;

- orientation of the roof: the roof is a north-facing pitched roof which promises little yield;

- Aesthetics: Sometimes it is simply just optical reasons that speak against a solar system on the house roof.

Facade as an alternative

As an alternative mounting location for a solar system, the façade of the building is ideal. Both solar power modules and solar heat collectors can be installed on the façade (usually with retrofitting of existing buildings) or integrated into the facade (usually in new buildings). The latter method of installation saves the costs that would be required for the façade design if no solar façade would be integrated.

Shadows and solar panels

It is also a matter of course for a solar water faucet to achieve the highest possible yield, which is to be achieved by the solar façade: the solar façades must be positioned strategically and oriented so that they capture as much solar energy as possible. It is also important to ensure that the solar façade is not shaded by trees, neighbors or the roof. Shading is also one of the main reasons for revenue losses. One reason for the fact that solar facades is less often used as a solar roof is, by the way, not the supposedly higher costs involved, but rather the fact that many architects or builders know too little about this technical alternative to a solar roof.

Inclination of roofs

An important difference between a soalr roof and a solar facade is the angle of inclination in which the plant receives the sun's rays. The following applies: A module / collector mounted vertically to the façade yields about 30 percent less solar energy than a diagonally raised component on the solar roof. But vertical is not the only method of installation when it comes to solar panels: the PV modules or ST collectors can either be built either vertically to the façade or can be removed at an angle from the vertical using a special device (mounting, etc.).

Source: http://www.energie-experten.org/erneuerbare-energien/solarenergie/solaranlage/solarfassade.html