The solar panel output varies depending on various factors. Putting solar panels at the optimal angle and to the best orientation is essential to obtain the maximum energy in a solar power system. This article discusses the following:

• Why do solar panel orientation and angle matter?
• Factors affecting solar panel orientation and angle
• How to calculate the best orientation and angle?
• Recommended portable solar panels with built-in brackets
• FAQ

Why Do Solar Panel Orientation and Angle Matter?

Prior to understanding why solar panel orientation and angle matter in a solar power system, we need to know how a solar panel collects energy from the sun. Solar panel cells only collect a specific wavelength during absorbing radiant energy from the sun. The absorbed radiant energy is then converted into electricity through a process called the photovoltaic effect.

Ideally, to optimize energy capture, you should put solar panels perpendicular to the sun rays to allow the solar panel to absorb as much radiant energy as possible, resulting in the highest production efficiency. However, the sun movement varies specific to the geographic location, season, and time of day. This makes the orientation and angle of solar panels important in maximizing the solar output.

Factors Affecting Solar Panel Orientation and Angle

Solar Panel Orientation

Solar panel orientation refers to the cardinal direction the panel is facing: north, south, east or west. To be more specific, the orientation refers to the horizontal direction of solar panels in relation to the equator. It is the true or geographic direction that points directly towards the geographic pole, a fixed point on the Earth’s globe. It differs from the magnetic direction to which a compass needle points. For instructions on how to find the true north, refer to How to Determine True North?

As the sun moves from the east to west around the equator, and the sun's path across the sky is the highest in the southern part of the sky for the Northern Hemisphere, and vice versa. Therefore, the geographic location of the installation site in relation to the equator determines the solar panel orientation. To maximize their exposure to sunlight throughout the day:

• In the Northern Hemisphere: Solar panels should preferably face the true south.
• In the Southern Hemisphere: Solar panels should preferably face the true north.

Solar Panel Angle

The solar panel angle, also known as inclination, refers to the vertical tilt angle between the surface of the solar panel and the ground.

As the sun movement varies both geographically and seasonally, you need to adjust solar panel angles specific to the latitude, season, and time of day to maximize the power output. In addition, you need to consider the protection against rainwater, connection methods, and roof shading.

• Latitude

Ideally, the angle of your solar panels should be equal or close to the latitude of where they are installed. As you go further north or south, the angle of the sun in the sky decreases. To efficiently capture sunlight, solar panels need to be tilted a steeper angle. For instance, the recommended tilt for a solar panel system in Detroit (42° N) is steeper than what's suggested for a system of the same size in Los Angeles (34° N).

• Season

The optimal tilt angle for your solar panels is influenced not only by your location but also by seasonal changes in the sun's position. In summer, the sun is higher in the sky, while in winter, it sits lower. As a result, adjusting the tilt of your panels seasonally is necessary to maximize their energy production. In winter, increase the title angle of solar panels while decrease that in summer.

• Time of day

If connected to a stand-alone power system, the installation angle of solar panels should be based on the light conditions to obtain the maximum power output. Generally, if the output of the solar panels can be met even on the lowest light intensity of the year, then the solar output the chosen angle will meet the year-round demand.

• Protection against rainwater

It is recommended that the mounting angle of solar panels be not less than 10 degrees (RV depending on the actual situation), so that the surface dust of the solar panels can be easily carried away by rainwater when it rains, thus reducing the number of cleaning. Furthermore, tilting solar panels less than 10 degrees facilitates the flow of water on the surface of solar panels, thereby preventing the accumulation of a significant quantity of water over an extended period, which could otherwise result in the formation of stains on the glass. This, in turn, can have a detrimental impact on the visual appeal and operational performance of solar panels.

• Connection methods

Serially connected/parallel connected modules should be installed in the same orientation and angle. Different orientations or angles may cause different amount of solar radiation received by each panel, which may lead to output power loss. To maximize annual power production, the optimal orientation and tilt of the solar panels in the area where they are installed should be selected to ensure that sunlight can still reach the solar panels even on the shortest sunny day of the year.

• Roof pitch

Roof pitch or slope is also important factor that you need to consider when calculating solar panel angles. The tilt angle of solar panels should ideally align with the sun's path across the sky to maximize sunlight exposure. The roof pitch determines the initial angle which the panels are installed, and adjusting the tilt angle accordingly ensures that they receive sunlight more directly.

• Roof shading

Roof shading is another factor that you need to consider when installing solar panels. For solar home applications, the roof area with the optimal solar panel placement may be shaded by a taller building or trees. In the event of shading, you should consider utilizing alternative, unshaded areas, even if the resulting panel orientation is not optimal.

How to Find the Best Orientation and Angle?

As the solar panel orientation and angle vary geographically and seasonally, finding the best orientation and angle for solar panels is relatively easy once you get a clear idea of your location and installation environment. Follow the steps below to get started:

Step 1: Find the Location Altitude.

Finding the exact location where you are installing your solar panels means that you need to find out the latitude. You can simply search your location's latitude on Google, or read the latitude on a map.

The letter N or S behind the degree number represents the Northern or Southern Hemisphere.

For latitudes ending with N, face the solar panels to the true south, and do the opposite for panels installed in latitudes ending with S. For instructions on finding the true north or south, refer to How to Determine True North?

Step 2: Calculate the Optimum Tilt Angle.

An ideal angle for your solar panels will be equal or close to the latitude of where you are installing your solar panels. Therefore, a typical angle is between 30° and 45°. However, a proper solar panel angle will fluctuate over the course of the year. There are two calculation methods that are popular in the industry.

Method #1:

Calculate the tilt angle specific to seasons.

Add 15° to the altitude in winter and subtract 15° from the altitude in summer. This helps solar panels get the maximum energy radiation specific to seasons.

For instance, Detroit is a latitude of 42° N. The optimal angle for solar panels in winter should be 42° + 15° = 57° in winter and 42° - 19° = 23° in summer.

Method #2:

This method provides more accurate angles than Method #1 by taking into consideration of impact of latitude, seasons, and time of day. See the table below for the formulas.

In the example of Detroit, the optimal tilt angles for solar panels are as follows:

• For winter: Optimal Tilt Angle = 42° x 0.9 + 29° = 66.8°
• For summer: Optimal Tilt Angle = 42° x 0.9 - 23.5° = 14.3°
• For spring and fall: Optimal Tilt Angle = 42° - 2.5° = 39.5°

Step 3: Access Your Installation Environment

Environmental factors such as the roof pitch, climate, and site conditions also affect the orientation and angle for solar panels in a solar power system.

• For roof installations, determining the optimal tilt angle for mounting your solar panels involves subtracting your base tilt from your latitude, and then adjusting it accordingly. You can watch How to Find Roof Pitch in Less than a Minute? to find the roof pitch.
• For rainy and snowy areas, consider protection against rain and snow. Rain and snow accumulation reduces and even blocks sun rays, so put solar panels steeper angles in these areas to mitigate the impact from rain and snow accumulation.

Choosing proper mount brackets also plays an important role in maximizing the solar output specific to your installation site. The table below lists some popular brackets for solar panels provided by Renogy.

*The mount brackets do not come with solar panels, and the listed photos are for demonstration purpose only.

Recommended Portable Solar Panels

In addition to separate mount brackets, you can use portable solar panels that are integrated with brackets to simply installation.

FAQ

Q1: Which Matters More: Solar Panel Orientation or Angle?

Prioritizing solar panel direction over angle is recommended. While achieving the optimal tilt can enhance output by approximately 5-8%, orienting the system southward can increase efficiency by up to 30% or more.

Q2: Any Recommended Tools to Help Calculate the Orientation and Angle for Solar Panels?

Yes. We recommend two tools for your reference.

• For finding the latitude of your exact location, visit Latitude and Longitude Finder.
• Use World Bank Global Solar Atlas website to find the PV power output, direct normal irradiation, air temperature, optimal PV tilt angles, and more of where you are installing your solar power system.

Q3: Is There a Best Angle and Orientation that Fits All? Any Recommendations?

There isn't a one-size-fits-all answer. The sun's position varies throughout the day and the seasons, making it challenging to determine a permanent ideal position for solar panels. Assess the direction the solar panel will face and adjust the tilt angle accordingly. Utilizing calculation methods outlined in resources like "How to Find the Best Orientation and Angle" can assist in determining the optimal orientation and angle for your specific location and needs.

Q4: At What Angle Do Solar Panels Stop Working?

Solar panels do not stop functioning certain angles, but some angles decrease the output efficiency. They stop working when covered or blocked from sun rays.

Conclusions

To sum up, solar panels in the Northern Hemisphere should face the true south while those in the Southern Hemisphere should face the true north. The tilt angle for solar panels varies specific to your location latitude, season, and time of day. Typically, an optimal angle sits between 30° and 45°. To maximize the energy conversion efficiency, use proper mount brackets, and adjust the angles and orientation in accordance with time of year and day.