o, you’ve determined that your location is suitable for solar - you're among the lucky ones! There is yet another thing to consider if you want to make good use of solar power: solar panel direction. Let's break down why it makes a difference and how to set up your PV panels right.
Why the orientation of solar panels matters
Solar panels generate electricity by harvesting sunlight: the moment it reaches their surface, the electrons within solar cells are set into motion, which creates an electric current. Therefore, the more sun rays the panels capture, the more energy they produce - it's as simple as that. And though we can’t control the weather and the amount of sunshine in our area, we can still ensure we make the most of what we get.
Proper positioning helps your solar panels collect as much sunlight as possible. When the panels face the sun all or most of the day, they receive more energy resources, which in turn means more significant savings on electricity bills.
What solar panel direction is the best?
South direction of solar panels
Since the Earth is a sphere, sunlight isn’t evenly distributed over the planet. Sun rays fall on it at an angle, which is why some parts of the world enjoy more solar irradiance than others. While being almost 90˚ at the Equator, the pitch gets smaller toward the north and south poles. Therefore, your panels will receive the most direct sunlight if they face the Equator, so in the Northern Hemisphere, the solar panels will achieve the maximum possible electricity output when facing south. Meanwhile, north facing modules work best in the Southern Hemisphere.
Some may argue that south facing panels will generate the most electricity midday while it is most needed in the mornings and especially evenings when the sun is down. However, it is not really an issue if you have net metering (or NEM) in your area.
Net metering is a billing mechanism that allows solar owners to send any extra electricity their panels generate to the local utility ongrid solar and earn credits that can be used to reduce monthly electric bills. Most U.S. states offer one-to-one credits for solar power, meaning the electricity you feed to the grid is equal in value to the one you draw from it. So if 1:1 NEM is available where you live, south facing panels will help you produce plenty of energy during the day and sell any surplus to the utility.
For a similar reason, solar panels that face south help homeowners reap the full benefit of battery storage. If your panels are paired with battery storage, you would want to generate as much solar electricity as possible to charge the battery and use this power later in the evening or at night. South facing panels will harvest maximum direct sunlight during the day and save it for later.
So as a general rule, facing your solar panels south is the best solution that will allow you to tap into the full potential of your PV panel system.
West and east solar panel orientation
Even though the south solar panel direction is considered the best, it is not always an option. But that doesn’t mean you can’t go solar; it only means that your yield will be slightly lower.
The output of east and west facing solar panels will be around 15% to 20% less than that of south facing ones. There are, however, cases when this solar panel direction makes even more sense. For example, some large-scale solar farms use a so-called east-west layout – the rows of lightly tilted panels that lay back-to-back to form a peak, with each row facing east or west. As the site area for solar projects is often limited, squeezing more panels into a limited space can turn out to be more economically advantageous in terms of the Levelized cost of electricity (LCOE).
But east and west facing panels can also be reasonable for residential PV panel installations. As we’ve already mentioned, the south solar panel direction enables your panels to harvest more direct sunlight during peak sun and hours and send the excess electricity to the power grid. But if you don’t have net metering in your area, you will be selling your solar energy at a loss. So if that is your case, you should definitely consider the panels that face east and west.
Whereas south facing solar modules produce the most electricity during 4-4.5 peak sun hours a day, east and west facing panels offer a flatter power generation curve delivering output during a greater number of hours per day. This is ideal if you want to rely on self-consumption and match your solar power use to your lifestyle. East-west facing solar panels will produce less energy when you’re gone for the day, but you will see higher output early in the morning and late in the evening when demand is usually higher.
North solar panel direction
For those living in the Northern Hemisphere, north facing solar panels is the poorest choice. The panels that face north will receive less direct sunlight resulting in significant output losses. This solar panel direction can cut the output by as much as 30%, which may be particularly disappointing given the high cost of PV installation.
How to place solar panels so that they face the sun longer
If your roof doesn’t face south, you can still have solar panels and enjoy both the environmental and cost-saving benefits of solar power. There are a few tips for increasing the output no matter what direction your PV modules face; one of them is installing PV panels on the ground. Suppose your property has enough space that isn’t shaded by obstructions. In that case, a ground-mounted PV panel system will allow you to freely choose the solar panel direction, which means you can place your panels in such a way that they harvest maximum sunlight.
Another way to enhance the effectiveness is to install a solar panel tracking system that follows the sun as it moves across the sky. Modern 2-axis trackers can significantly increase the amount of direct sunlight the solar panels collect, boosting energy production by up to 40%! The one major downside is the hefty price tag of $500-$1,000 per panel.
Best tilt for solar panels
Apart from solar panel direction, the tilt is another factor that impacts the amount of electricity PV panels can generate. The angle of inclination depends on both your location and the season. As a rule of thumb, it should be the same as your site’s latitude so that the sunlight can hit them at as close to a 90° angle for as much as possible. So the further your home is from the Equator, the higher your solar panel tilt angle should be. Most solar panels in the US are installed at a tilt between 30° to 45° relative to the horizon.
The optimum solar panel tilt also goes up and down with the change of seasons. Since the sun is approximately 15° higher above the horizon in summer, to calculate a perfect summer tilt angle subtract 15° from your latitude. Conversely, add 15° to your latitude to find the best winter angle. Ideally, the tilt of solar panels should be adjusted twice a year to ensure the panels get maximum solar radiation.
Final thoughts on solar orientation & tilt
Considering all of the above, south facing PV panels with a 30°-45° tilt angle work best for most American solar shoppers. However, every rule has an exception, so it’s always best to consult your solar panel installer and find the best direction for solar panels.