Does my roof have to face south for solar to be worthwhile?
Published on August 29, 2018 by Andrew Sendy
Last updated on January 10, 2019
8 minutes read
Categories: Solar 101
If you're looking to install a solar system in your home, you'll want to position your panels to receive maximum exposure from the sun. But which direction will provide that? And what if your roof doesn't face that direction? Will you still be able to amass enough energy savings to make solar energy worthwhile? Learn more about solar panel installation as we explore their positioning and how it affects your energy output.
Which is the best direction for solar panels to face?
The sun rises in the east and sets in the west, so you may think that one of those directions would be ideal for solar panel positioning. But in fact, the way the sun moves across the sky favors the south. As such, in the northern hemisphere, south-facing panels will provide you with the most direct sunlight. Find out how much installing south-facing solar panels will cost for your home!
How do south-facing solar panels compare to other directions?
In mid-afternoon, when the sun is at its peak in the sky, it's shining towards the south. Therefore, you'll maximize your energy production when your panels face that direction.
Experiments have been conducted in some large cities in the northern hemisphere, under a variety of weather conditions, on panels facing all four primary directions. And the verdict is, south-facing panels produce more energy than any other direction.
But what if your roof faces east/west instead of north/south? How much energy will you lose if your panels don't receive direct sunlight at peak hours?
How much less energy do west-facing solar panels produce compared to south-facing solar panels?
If your solar panels face west, they'll receive their direct sunlight as the sun is setting, in the late afternoon and early evening, rather than when the sun is at its peak. This lack of exposure to direct sun at peak times means you'll lose about 20% of your energy output compared to a south-facing system. This loss can be at least somewhat offset by installing a bigger system. Find out what size solar system you need to reap maximum energy benefits.
Despite the loss in overall energy production from west-facing panels, some folks are now considering positioning their panels facing west to maximize energy production in the late afternoon - the time when peak energy prices are in effect.
This consideration is especially important to consumers in California, who now have to use time-of-use electricity plans where power is more expensive in the late afternoon and early evening.
How much less energy do east-facing solar panels produce compared to south-facing solar panels?
East-facing panels receive direct sunlight in the morning, as the sun rises. They likewise produce about 20% less energy compared to south-facing panels. However, for both east and west-facing systems, if you change the tilt of your panels from 30 degrees to 15, the energy loss compared to ideal conditions is only approximately 15%. Discover how much money you can save with a solar installation.
Is it better to face your panels west if your utility enforces time-of-use electricity rates?
There's an exception to the "south-facing is best" rule, and that's if your utility adjusts their rates based on time-of-use and charges more during peak hours. In most areas, time-of-use rates go up from about 3 pm to 8 pm.
South-facing panels get maximum exposure at noon when the sun is highest in the sky. But west-facing panels get more exposure in the later afternoon and early evening, as the sun is setting. Therefore, they'll produce more energy during those peak hours when it costs more to get it from the grid.
How do different weather patterns affect efficiency?
Since solar panels rely on direct sunlight, sunny weather is vital to their efficiency. But it can't be sunny all the time. Will other weather patterns limit your panels' effectiveness? Not necessarily.
Rain, for instance, can be beneficial to your panels. Although there is less sunlight exposure, the rain can wash away dirt and debris that would otherwise get in the way of sunlight collection, giving you more energy going forward.
Most other weather phenomena - including wind, snow, hail, and lightning - your panels are built to withstand. These things will have an impact on energy production, but the solar panels will still produce some electricity during these times.
Ironically, excessive heat can lower solar panel output because it causes greater impedance and voltage drop. The extent to which power output falls as the temperature of the cells inside the solar panels increase is called the temperature coefficient. The lower the temperature coefficient, the less that the output of the panel falls as heat increases.
A better panel will have a lower temperature coefficient. You can find the solar panels with the best temperature coefficient by using the solar panels comparison tool on SolarReviews.
The same solar panel comparison tool will also allow you to find what are the most efficient solar panels on the market today.
Are solar panels effective in cloudy areas?
It's a common misconception that solar panels only benefit people who live in extremely sunny areas, such as Los Angeles or Phoenix. Even if you live in a city where you see clouds more often than the sun, you can still experience tremendous energy savings with a south-facing solar system.
Whether it's cloudy, rainy, or foggy - as long as it's daytime, and you can see, then light is coming from the sun and can reach your solar panels.
What can you do to optimize your solar system's efficiency?
There are several ways to ensure you get the maximum benefit from your solar panels.
An automatic solar tracker follows the sun across the sky, to maximize your exposure throughout the day. Or, if a solar tracker is a bit out of your price range, you can adjust the angle of your panels manually at critical points throughout the year, to improve exposure.
Your solar provider can help you determine how to adjust your panels to receive maximum sunlight. Get the facts on how much an average solar energy system will cost for your home.
Is it still worth it to go solar if you don't have a south-facing roof?
Absolutely. No matter what direction your panels face, they'll still provide plenty of energy to your home to offset your electric bill. Find out more about how you can start saving with solar.
South-facing solar panels provide you with maximum energy savings for your home. But no matter what direction your roof faces, you will still see a significant impact from solar power.
Solar panels will save you money and energy year-round - in any weather, rain or shine. Get an estimate of the benefits you can receive from a solar system today!