What Direction Should Solar Panels Face?
If you live in the USA or any other country in the Northern Hemisphere, the best direction to face solar panels is south. Since most sunlight comes from the south, this will make your panels more productive. However, if the local power company charges higher prices in the afternoon, your panels should face west to maximize the dollar savings.
The electricity output of solar panels is directly related to how much sunlight they receive. Therefore, you should install them on the sunniest part of your rooftop. Also consider that solar panels are not productive when in shaded areas, and they represent a wasted investment. You can find out more about this by reading our article on solar panels in the shade.
If you are charged constant kilowatt-hour prices, your goal should be maximizing the electricity production of solar panels. However, if you are charged variable kWh prices throughout the day, solar panels should maximize production when the highest prices are being applied. This will increase the savings on your power bill.
Why Do Solar Panels Produce More Energy When Facing South?
To maximize the return on investment, the first step is knowing where to install the solar panels. Since the Earth is a sphere, sunlight reaches each geographic location with a different angle. If you track the sun’s position in the sky for an entire year in the USA, you will notice it is mostly towards the south. As a result, solar panels facing south produce the most electricity.
Consider reading about how a solar panel works before moving forward. Different results can be expected based on its orientation:
- Since the sun rises in the east, solar panels facing in that direction are more productive in the morning.
- On the other hand, west-facing panels are more productive in the afternoon, since the sun sets in that direction.
- Installing panels that face north is not recommended, since it results in the lowest electricity output.
As you move farther to the north, the sun has a lower position in the sky and solar panels must be tilted more. In locations that are not far to the north, such as Florida or Texas, solar panels do not need a drastic tilt. However, if you must use them in Alaska, they must be tilted almost vertically to collect as much sunlight as possible. Qualified solar installers can determine the optimal tilt angle based on your geographic location. We can help you when it comes to choosing a solar installer.
Make sure you get an inspection of your property to find the best areas for a solar energy system. Consider that the size of a panel does not affect the optimal orientation: the recommendations above apply for both 60-cell and 72-cell panels. You can read our article about the importance of the size of a solar panel for more information.
The efficiency of solar panels is not affected by their orientation either. The electricity output varies because the amount of incident sunlight also varies, but the conversion from sunlight to electricity is not affected. If you’d like to know more, take a look at what we’ve written about solar efficiency.
How Electricity Tariffs Affect the Optimal Solar Panel Orientation
Your panel can have different monetary values, so it’s important to know about the energy produced by a solar panel. If you are always charged the same kilowatt-hour price, your goal should be getting maximum production from solar panels.
However, many electric companies apply time-of-use (TOU) tariffs, which change throughout the day. The highest kWh prices are normally billed in the afternoon and evening, since that is when the grid faces maximum consumption. There are many factors that increase operating costs, and this leads to higher tariffs:
- Electric companies must bring more power plants online to meet the peak in consumption, including the plants with high generation costs.
- Since power lines and transformers are carrying a high current, they waste more energy as heat emissions.
- Electrical faults are more likely when the grid is burdened, creating a higher risk of blackouts.
Many power companies apply higher electricity prices at times of peak demand to compensate for their higher operating cost. The high kilowatt-hour price also disincentives consumption in homes and businesses, helping unburden on the grid.
As previously mentioned, solar panels become more productive in the afternoon if they face west. If you are charged a TOU electricity tariff, you can take advantage of this. A solar power system facing south will produce more kilowatt-hours than an identical system facing west. However, if the kilowatt-hour price increases sharply in the afternoon, your dollar savings will most likely increase.
Solar Panel Orientation Tips for Roof and Ground Systems
When finding the optimal orientation for solar panels, a ground installation offers more flexibility than a roof installation.
With a rooftop solar system, you are limited to the orientations and slopes of your existing roof sections. If an optimal solar panel placement is not possible, you may need to purchase additional panels to increase generation. On the other hand, with a ground solar system, you can adjust the orientation and tilt angle of panels for maximum productivity.
While ground solar systems offer more flexibility for positioning, they also have their limitations. In the first place, you must have a property with enough ground space for solar panels, while a rooftop installation does not need extra space. Also, since a ground solar system has a lower elevation, finding a spot without shadows can be more challenging. If you need more information on how all of this works, feel free to take a look at our article about solar installation.
Since each property is unique, the best recommendation is getting a professional inspection and a customized solar panel system design. Getting quotes from multiple solar companies is also recommended, since you can compare several options and find the best deal.
NASA Parameters for Tilted Solar Panels