Photovoltaic knowledge

The correct alignment of a solar system

How do orientation and tilt angle affect the energy yield of a solar installation? We can tell you which factors you should consider.

13 February 2024 | 8:32

Roofs and house walls, open spaces and dual-use areas - photovoltaic systems are one of the key solutions in the energy transition. New construction without PV is no longer conceivable. In the run-up to a renovation, it is also checked whether the use of a solar system is an option. But what if the roof is not perfectly aligned to guarantee full solar yield? We can tell you how the alignment and angle of inclination of a photovoltaic system interact.

The optimum alignment and inclination of a solar installation

In order for a photovoltaic system to convert sunlight into electricity, it must receive as much sunlight as possible for as long as possible. This means that the solar modules should be aligned towards the sun in such a way that they can collect as much energy as possible.

But it's not that simple. The earth does not stand still. It changes its position in relation to the sun over the course of the day and the year:


  • The sun is at its highest at midday.
  • If the sun is on its orbit between the equator and the Tropic of Cancer (21.3. to 23.9.), it is higher above us. If, on the other hand, it is on its path towards the Tropic of Cancer (23.9. to 21.3.), it rises only very slightly above the horizon.

The angle at which the sun's rays hit the ground, a house roof or a wall therefore varies depending on the time of day and the season. In addition, the individual topography of the surroundings influences the solar yield.


These factors must be taken into account if a solar system is to work efficiently. When designing the system, it is important to find the best compromise between all influencing factors based on the operator's objectives.

What alignment options are available?


In principle, solar modules can be aligned in all directions. The most common orientations are south and east-west.

As the sun is at its highest in the south, it makes sense to position the modules in this direction. PV modules facing south reach their peak values in the midday sun. If the electricity produced cannot be stored, it makes sense to feed surplus electricity into the grid.

With an east-west elevation, the constant yield is maximized over the course of the day. For this reason, east-west elevations are recommended if the electricity is to be generated for self-consumption. For flat roofs, an east-west orientation may even be the more efficient solution.

Alignment and tilt angle

Photovoltaic systems produce the highest solar yield when the sun's rays hit the solar modules at a 90° angle. However, in Europe, and therefore north of the Tropic of Cancer, the sun's rays never hit the ground at a 90° angle. The solar modules must therefore be set up at an angle depending on the ground or roof conditions.

When planning a solar installation, the angle of inclination is therefore calculated at which the modules can receive the most sun over the course of the year. In this position, the maximum annual yield of the system can be achieved depending on the location.


Good to know:


Rule of thumb Orientation: The further the orientation deviates from the south, the greater the reduction in yield. With a deviation of 45° to the east or west, a yield reduction of 5 to 10 % is assumed.


The rule of thumb for the tilt angle: the further the orientation of the system deviates from the south, the less the modules should be tilted.


Here too, our experts will be happy to calculate the best solution for your project.


Suboptimal alignment and inclination of a solar installation

The further the orientation and inclination deviate from the optimum, the lower the solar yield with which the PV system can operate.

However, positions that deviate from these ideal orientations can also make sense if they suit the objectives of the system operators. Almost all orientations from south-east to south-west are therefore suitable.

When it comes to alignment, we aim for the best possible alignment based on your goals and calculate how much solar yield you can expect.

Photovoltaic tracking systems

If the position of the sun changes over the course of the day and year, why don't we move the solar modules with it? Photovoltaic tracking systems do exactly that. A distinction is made between single-axis and dual-axis tracking systems.

However, because tracking systems are space-intensive and expensive compared to the solar yield, they have rarely been used to date.

Calculation of the inclination of solar systems

Tools such as the Global Solar Atlas or the European Photovoltaic Geographical Information System provide a good overview of where in the world you can expect solar radiation.


How your solar installation should be aligned and tilted depends on all the factors mentioned above. Online calculators can give you a rough estimate. Their shortcoming, however, is that you do not have essential information that only you as the owner of the roof or the site know or that can only be gathered on site.


Does a nearby mountain cast shadows on the system? What about chimneys, satellite dishes and other roof structures? Are there trees overhanging the roof nearby? Our teams of experts will calculate the perfect alignment and optimum tilt angle for your project and show you your options.


Do you have a specific project? Please contact us.


  • Which orientation is best for installing a solar system?
    A south-facing orientation with an angle of inclination that maximizes the time in which the sun's rays can reach the solar modules at a 90° angle is ideal for installing a solar system. However, it is not possible to say in general terms which orientation is best for your project. The location, topography and other factors influence how well a PV system can work.
  • How does the orientation affect the energy production of a solar installation?
    As a rule of thumb, the further the orientation deviates from the south, the lower the energy yield. A deviation of 45° is assumed to result in an energy loss of 5-10 percent.
  • Which orientation increases the output of a solar energy system?
    A south-facing orientation ensures that the maximum amount of energy can be generated at midday with the maximum amount of solar radiation. However, an east/west orientation may be the better solution over the course of the day. We will be happy to calculate the maximum output for your project based on your individual circumstances.
Helmut Weiss
Head of Marketing & Communications
+ 49 (0) 9225 95500 h.weiss@pmt.solutions contact now
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