Understanding Tilt & Azimuth Angle in Solar Design | Reo Solar Experts

In this blog, we’ll have a look at what is a Tilt Angle & Azimuth Angle of a solar power plant, try to understand how to find the best Tilt and Azimuth angle for your solar plant and how it plays a vital role in solar design.

What is a Tilt Angle?

To understand the tilt angle of a solar plant is, follow the illustration below. In solar design, a tilt angle of a solar plant is the angle formed between the horizontal plane and the pitch of our solar panels.

A Solar Panel with 45 Degrees Tilt Angle
Pitch of the Panel is always calculated against a Horizontal Plane

However, an important thing to note here is the word horizontal plane. A tilt angle of a solar plant is always measured with respect to a horizontal plane.

What do I mean by that?

Well, let us consider two different examples. In example 1, we have a flat roof with the solar panels placed flat on the roof surface. In example 2, we have a sloped roof or a tilted roof and the solar panels are placed flat on the roof surface.

In both the cases, since the solar panels are placed flat on the roof surface, they must share a similar tilt angle of zero degrees, right? No!

Although they are both laid flat on the roof surface, the tilt angle is different in both cases as the tilt angle is always calculated against a horizontal plane.

In example 1, we have the solar panels laid flat but they are also flat with respect to the horizontal plane and thus have a 0 degree tilt.

In example 2, the solar panels are laid flat on the roof but they are at a certain angle with respect to the horizontal plane, and thus make a tilt angle of 30 degrees (equal to the slope of the roof)

A Solar Panel with 45 Degrees Tilt Angle

To summarize, we can say that the tilt angle is the angle formed between the solar panels and the horizontal plane irrespective of the slope of the roof or the mounting structure.

Why do we need a Tilt Angle?

While designing your system, when panels are placed flat against the horizontal plane, the solar rays which are required to generate electricity, strikes on an angle and forces majority of the ray to reflect back. This is why we tilt the panels a bit such that the sunlight incidents the panels perpendicularly as shown in the below illustration and the sunlight is perpendicular to the solar panels which allows most of the sun rays to be absorbed.

What is the right Tilt Angle for my location?

So far we have understood what the tilt angle of a solar panel means and why it’s important. Now how do we chose the right tilt for our location?

To answer this question, let’s have a look at the daily movement of sun. The sun’s angle moves greatly during the year, and as a thumb rule, we understand that the sun’s mean position is generally equal to the latitude of your location. Let’s take an example, we are positioned in Kochin, Kerala, India (which has a latitude of 10 Degrees).

Now we know that at a latitude of 10 degrees, the mean position of the sun is 10 degrees. We now have three positions of tilt angles to choose from.

  1. Tilt our solar panels towards the mean position
  2. Tilt our solar panels towards the winter position
  3. Tilt our solar panels towards the summer position

Now, our choice of tilt greatly depends on what is the application of your solar plant and when we want to generate the maximum energy from our power plant. If our goal is to generate the maximum amount of energy during the summers to power the air conditioning units, tilting our solar panels towards the summer position of the sun would benefit us greatly. If our goal is to generate the maximum amount of energy during the winters to power the heating units, tilting our solar panels towards the winters position of the sun would help us greatly.

However, in most cases, simply facing the panels towards the mean position of the sun would be the best solution for our use case.

As a basic thumb rule we can say that the ideal tilt of our solar plant should be approximately equal to the latitude of our location. So in our case, since the latitude of the location was 10 degree we would generally tilt the solar panels at 10 degree latitude.

Let’s move on..


What is the right Azimuth Angle for my location?

Now that we have understood tilt angle, let’s try to understand what the Azimuth Angle of a Solar Plant is. In simple terms, the azimuth is the direction your solar plants are facing.

Let’s get started by understanding a simple compass. A typical compass has North at the top that’s denoted by 0 degrees, East is denoted by 90 degrees, South is denoted by 180 degrees and West is denoted by 270 degree.

Similarly, the azimuth angle of a solar panel is also denoted in degrees. Let’s go back to our previous example to understand the azimuth angle a bit better.

What is an Azimuth Angle?

Here we have a flat roof where our panels are tilted at an optimum angle of 10 degrees. Now the question here is where should my panels face to receive maximum sunlight and perform optimally?

Once again, we have a few options,

  1. We can face the East, where the sun rises
  2. We can face the West, where the sun sets
  3. We can face the South, where we can receive sunlight throughout the day (Note – you would face the northern direction if your site is in the southern hemisphere)

Now the problem with facing our panels towards the east or the west would mean we would miss out energy generation for half a day which is not optimum. Facing them at an average direction where we can receive sun rays both during the early and late hours seems to be the appropriate solutions. Hence if we face our solar panels towards the south, the panels are exposed to the sun for the entire day and we get maximum generation. 

Going back to our compass, we know that the south is 180 degree and hence if our panels are facing true south, the azimuth angle for this case would be 180 degrees.

The azimuth angle of a solar power plant is basically an angle which describes the position of our solar panels with respect to north.

However, in many cases you may not be able to place your panels facing 180 degrees due to certain restrictions. For example, in the scenario below, it’s not practically possible to face true south on the house with a sloped roof as the orientation of the house does not allow us to do so. In such cases we find the closest practical azimuth to true south after inspecting the site and place our panels accordingly


In conclusion, you can find the right tilt and azimuth angles using simple thumb rules. However, if you truly want to optimize your power plant to operate like a beast, you need to design & simulate your power plant with different conditions and see which conditions generated the most amount of energy. These simulations can be performed on various software including the industry leader – PVSyst and SketchUp.

How to get started with PVSyst & SketchUp?

For an in-depth understanding of these software, you may check out the online solar training programs and courses provided by Reo here. 

Enrol in Reo Training’s PVSyst course with:

  • 9 hours of online course videos
  • 12 downloadable files, datasheets and Excel calculators
  • 4 solved solar design case studies
  • 6 unsolved solar design practice case studies
  • 4 out-of-syllabus bonus lessons
  • Progress tests and assignments
  • Exclusive mentor and peer community
  • Detailed performance feedback
  • Certificate of Completion

Our courses are designed by professional solar engineers who have vast international experience in designing and executing solar projects. With their experience, we’ve built solar courses that are complete with case studies, international best practices, and solutions to real-world problems

What’s the difference between PVSyst, SketchUp & Helioscope? Read Here

For any more questions, we’re right here. Until Next time!

We use cookies to give you the best experience.