When installing solar panels on your roof, ensuring that your panels are positioned to face the best solar panel direction should be your top consideration. Failure to do so can lead to a poorly performing system meaning fewer savings, a sluggish payback period, and a substandard ROI. This article will explain the importance of solar panel direction as well as in what direction should solar panels face.
Why Is Solar Panel Direction Important?
Knowing why the direction of your solar panels is important for their performance first requires you to understand how solar panels work. A solar panel is comprised of a large number of solar cells connected with one another in series and parallel formations.
When photons of light strike these solar cells, they energize the electrons within the semi-conductor atoms that make up the solar cells. Once the electrons have gained enough energy, they escape the atoms becoming free, mobilized electrons.
The conductors connected to the positive and negative terminals of the cells from a complete circuit allow the free electrons to flow through it, giving you current.
Knowing this, one can clearly begin to understand how the performance of solar panels is related to the amount of sunlight they receive. To put it simply, the greater the amount of solar radiation incident on your solar panels, the more electrical energy they will generate.
And so, to ensure that your solar panels deliver their maximum possible output, it is vital that your solar panels be installed in a direction in which they receive the greatest amount of average solar radiation as is possible for your area and roof.
It is important to remember that the best direction for solar panels is decided on the basis of average solar radiation instead of momentary values. This means that the direction of your solar panels will be such that the average radiation they receive in a day, month, or year will be maximum.
However, at any one moment in time, there will be another particular direction that will be able to provide your panels with a greater amount of solar radiation and hence facilitate greater power generation at that moment. But again, this will be only for that certain moment in time.
What Direction Should Solar Panels Face?
Generally speaking, for areas situated in the northern hemisphere of the earth, facing solar panels in a southward direction will provide the owner with the best system performance. This will allow you to achieve the largest possible electric bill savings and the shortest payback period.
Facing your solar panels in a southward direction not only maximizes the output of the system, but it improves the economics of your system in a few other ways as well. For instance, southward facing systems also allow the owner to take fuller advantage of net metering if their state allows it, and of their battery storage capacity.
Why Is South the Best Direction for Solar Panels to Face?
There are several reasons why the south is the best direction for solar panels to face. The three most important ones are explained below:
South Facing Solar Panels Generate the Greatest Output
We already know solar panels installed in a south-facing direction will perform the best and give the greatest electrical output.
This is due to the fact that the Sun shines almost directly above the Equator throughout the year on average. As such, if you’re located north of the Equator (northern hemisphere), facing south will offer the maximum amount of exposure to solar radiation.
And as we have discussed before, the more solar radiation your solar panels receive, the better they perform. Additionally, solar panels perform even better if the sunlight strikes the panel surface perpendicularly instead of at an angle, as is the case for southward-facing solar panels.
In fact, the Sun passes across the southern half of the sky all year for all places that are north of the Tropic of Cancer (23.4°N Latitude), which covers the whole mainland United States. In other words, solar panels in the United States that have been installed in a south-facing direction will be exposed to the Sun almost throughout the year.
South Facing Solar Panels Are Ideal for Net Metering
Net metering is an option that some states permit, allowing solar owners to sell any surplus energy their solar energy system produces to the grid. Knowing this, if net metering is available in your state, your primary focus should be on effectively meeting your daily energy requirements through your system while trying to generate surplus electrical power to sell to the grid and earn greater savings.
Having south-facing solar panels help you out in this regard as well. By now, it should be clear to you that solar panels facing south generate the greatest power overall, but did you know they generate the majority of it during the noon hours. At this time of day, the energy consumption for average American homes is at its lowest.
This means that there will be a lot of excess electricity generated during this time. With net metering being an available option for you, the more surplus energy you generate, the better because you may sell it to the grid in exchange for bill credits equivalent to the full retail value of electricity in your state. These bill credits can be used to further reduce your utility bill, thereby allowing you to save even more.
South Facing Solar Panels Are Best with Battery Storage Systems
Solar energy is a prospering technology with numerous benefits. Unfortunately, the technology is not free from having its own set of shortcomings. A major one is that it cannot produce electricity during the night and on overcast days.
However, pairing your system with an energy storage unit such as the tesla powerwall or any other solar battery can provide you with a way around this problem. This is so because if you have a solar battery coupled with your system, you can use the battery to store any surplus energy your system generates and use it to power your home at night when your system is inactive.
As such, your goal should be to generate as much power as possible during the day. By orienting your panels south, you should be able to generate enough electrical power to satisfy your daily needs while also having enough surplus power left to charge your battery. The battery can then be used to meet your power needs during peak hours, overnight, and during grid outages.
By combining south-facing solar panels with a battery storage device, you move a step closer to achieving self-sustenance for your energy needs. This means less dependency on the grid, or the ability to go completely off the grid.
Is a South Solar Panel Direction Always the Best Option?
While the south is the best direction for the solar panels to face for net metering, maximum system output, and charging up your solar battery, it may not be the best direction when Time of Use (TOU) billing is involved, and you want to reduce or completely eliminate your grid dependency during the peak hours.
TOU billing is when the rates of grid-supplied electricity change based on the time of day. Electricity becomes more expensive during the high-demand hours, known as peak hours, and, conversely, electricity becomes less costly as the demand for it decreases.
Since the grid-supplied electricity costs more during peak hours, it would be wise for a homeowner to use as little grid-supplied electricity as possible and instead rely on their solar energy system to keep their utility bill low. As such, your solar power generation becomes more valuable during the peak hours, and so your system should be oriented such that it produces more energy during the late hours of the day, which are the peak hours.
Due to the fact that solar panels facing in a southwest direction receive more solar radiation from the setting sun than south-facing panels, they are able to put out a greater electrical output during peak hours. However, this comes at a cost: the net solar production for the entire day will be lower than for south-facing solar panels.
As a result, the best orientation will be determined by how high the peak rates are in comparison to off-peak rates. The best orientation will be slightly west of south if peak rates are double the off-peak rates. However, if the difference is threefold or higher, the solar panels should be oriented in a southwest direction.
How Greatly Does the Solar Panel Direction Affect Its Output?
Orienting your solar panels in any other direction than the true south in the United States can lead to a decline in the performance and output of your system. The farther your panels are oriented from the south, the greater the hit their performance will take. Generally, the loss in performance is below 30%; however, in some extreme cases, the losses can go up to as high as 60%.
Solar panels placed on a roof looking southeast or southwest will typically provide around 8% less power than panels installed on a roof facing south under the same environmental conditions. Furthermore, solar panels installed in a west or east-facing direction will output about 15% less energy than panels facing south on the same pitch roof.
Roof panels installed in a north-facing direction, on the other hand, can see a performance loss of up to 30% compared to south-facing panels under the same conditions.
What If Your Roof Doesn’t Allow for a Southward Solar Panel Direction?
Many homes in the United States had their roofs installed decades ago. Unfortunately, roofs back then were not designed with solar installations in mind. Therefore, while a majority of roofs in the United States are solar compatible, it is likely that some people may find that their roofs are incapable of accommodating a southward solar panel direction.
You’ll be happy to learn that there are several ways you can work through this complication.
Install More Solar Panels
While a non-southward direction will reduce the performance of your solar panels, you can make up for this loss by installing a greater number of solar panels. A few extra solar panels shouldn’t push your budget too far.
This is one of the most practical and easy solutions to not having a south-facing roof.
Invest in Solar Trackers
If your budget allows, consider going for a tracking solar panel system instead of a fixed one. In a tracking system, the solar panels will follow the position of the Sun in the sky to maintain optimal exposure to the Sun throughout the day. These systems generate more electricity than your conventional systems.
On the downside, these systems are also much more expensive and require more maintenance due to the additional components such as the motor.
Install Solar Panels on the Ground
Another viable solution for not having a south-facing roof is to simply install ground-mounted solar panels in your backyard. An added benefit of such a system is that it would be very easy to clean and maintain. However, it will deprive you of your yard space.
Frequently Asked Questions (FAQs)
What Is the Best Direction for Solar Panels to Face?
The best solar panel direction for places situated in the northern hemisphere, including the United States, is a southward direction.
What Is the Best Angle and Direction for Solar Panels?
The best angle for solar panels is an inclination between 30 to 45 degrees.
What Is the Best Roof Pitch for Solar Panels?
Roofs having an angle of 45 to 85 degrees are ideal for rooftop solar installations.
Should Solar Panels Face North?
For countries located in the southern hemisphere, the best direction for the solar panel to face would be north.
Is A West-Facing Roof OK for Solar Panels?
East and west directions are generally acceptable for solar installations and will produce a good amount of solar energy.
The key takeaway of this article is that the south is the best direction for solar panels to face. Such an orientation allows your system to deliver maximum energy output, earn you greater savings through net metering, and reduce your dependency on the grid during night and overcast.
People who do not have a southward-facing roof or a roof that can accommodate a southward solar panel direction can either install a few extra solar panels to compensate for the performance loss or invest in solar trackers for ground-mounted systems.
The team at Firefly Solar is ready to answer your questions and give you a no-obligation price quote. Feel free to call us at 864-252-7858 or book a consultation online. And we’ll get in touch within 24 hours.