Improve the solar panel efficiency of your home solar system (2019 guide)
Written by Aditya Gautam
Updated March 12, 2020
4 minutes read
Categories: Solar efficiency
Do you already have a system installed at your home, or are in the process of getting them? Either way, you decided to shell out a fair chunk of change in return for clean energy and big savings on your power bills. You can maximize these benefits by ensuring that your solar panel system is operating as efficiently as possible. This article will show you how.
A quick note: In the process of researching and deciding on getting solar panels you will come across the term ‘solar panel efficiency’ a lot. The term solar panel efficiency can refer to two different things:
- The efficient installation and operation of installed solar panels (to achieve maximum electricity output); or
- The rated efficiency of a solar cell (its in-built capacity to convert sunlight into electricity).
This article focuses on the first meaning, i.e. getting your home solar panels to perform as well as possible.
(If you’re interested instead in the rated efficiency of solar panels, we address this briefly towards the bottom of the article, or you could read this article on solar efficiency rankings on SolarReviews).
Solar panel efficiency over time
Solar cells are bound to lose some efficiency as they age. This National Renewable Energy Laboratory paper quotes studies that show how there is a gradual decline in the efficiency of solar panels over time.
Today, most solar providers guarantee that the panels will maintain at least 80% efficiency for 25 years. However, the more premium brands promise a slower drop-off in efficiency; SunPower, for example, promises 90% of output after 20 years.
Other than aging, factors like the quality of the installation and dust on the panels can cause a significant decline in solar panel efficiency. Here are some tips on how you can ensure your panels keep performing at optimum efficiency.
5 tips for maximizing solar panel efficiency
As you get ready to harness the energy of the Sun, these simple tips will keep your solar panels happy and your electricity bills low.
1. Use a good solar installer
A good solar installer could be the difference between solar panels that work at optimum levels and panels that don’t. A badly installed solar system will never reach peak efficiency, hence hampering the return on investment you are expecting to get.
It might be a good idea to get quotes from a few local installers and then select the one that is experienced and has the necessary licenses. Here is how you can connect with the best solar installers in your area.
2. Install solar panels at the correct angle
This factor should be taken care of if you go with a good solar installer. You might still want to check the orientation of your panels and the angle they tilt at. In the long run, the angle can make a significant difference in energy production.
Generally, a tilt angle of 28°–30° is recommended.
Since we are in the northern hemisphere, you want to have your panels facing as close to south as possible.
3. Give the panels a clear view
A problem with conventional rooftop solar is that each panel is installed in groups called “strings.” Each string is a series of solar panels which are linked together. If one panel in a string is shaded it can stop the entire string from producing electricity efficiently. Imagine a shaded panel like debris clogging a water pipe.
The string of panels can only be as efficient as the weakest panel in the link. This is why only a tiny bit of shade can have a dramatic effect on the output of your solar panels. Try your best to ensure the panels have a clear opening to the sky at all times.
4. Keep the panels cool
As with all electronics, the efficiency of solar panels decreases as temperatures rise. Although the drop is not significant and is compensated by the long sunny summer days that are responsible for the temperature increase, it is a good idea to ensure a minimum gap of 7-inches between the solar panels and the roof. The gap will ensure easy movement of air and help cool down the panels.
5. Maintain for maximum solar efficiency
Research shows that accumulated dust can hamper the efficiency of solar panels. Although this seems to be more of a problem in countries like India and China, it can be the reason behind reduced panel efficiency in the US as well.
Clean your panels like you clean your car or your windows. If the panels are hard to access then there are plenty of companies that provide solar panel cleaning. For more details, you can read this comprehensive article on cleaning solar panels.
All other types of maintenance should ideally be done by a professional. Your solar installer is usually the best person for the job as they are already familiar with your solar setup.
What about the rated efficiency of a solar cell?
This is the efficiency that a solar cell is built to achieve. It refers to the percentage of sunlight hitting the solar panel that is converted to electricity.
Different types of solar panels can have different efficiency levels.The two most common available are monocrystalline solar panels and polycrystalline solar panels, which is what you see installed on most roofs. Monocrystalline solar panels tend to have higher efficiency ratings; polycrystalline have lower efficiency levels but are more affordable.
Is the rated efficiency important? In most cases, not really. A 300 watt rated panel will produce the same amount of power whether its a 22% efficient monocrystalline solar panel or a 16% polycrystalline solar panel. The main difference between the two is that the former will take less space on your roof.
If you want to learn more about the rated efficiency of solar panels and the most efficient solar panels on the market, check out this article on solar panels efficiency rankings in 2019
Use the 5 tips above to consistently receive the best performance from your home solar system. Keep in mind the angle of the panels, whether they are shaded or not, get them installed at least 7 inches above the roof and clean them when necessary. Working with a professional solar installer is usually the easiest way to achieve this.