There are over 2 million solar panel systems in the U.S. If you’re a homeowner, solar is a cheaper, cleaner energy source compared to fossil fuel-generated electricity. With potential savings of up to 100% on your energy bill, solar panels are a no-brainer.
Rooftops are the default location for installing solar panels because this takes up the least space. It also makes use of space that would otherwise go to waste.
Which solar panel should you use for your rooftop installation and why? That’s the question we want to look at as we examine some of the different types of solar panels. By the end of this article, you will know which is the most recommended solar panel and why it is preferred over other types of panels.
Which Solar Panel Is Best For Rooftop?
There are three main types of solar panels most commonly used for rooftop installations. These are polycrystalline, monocrystalline, and thin film. Monocrystalline solar panels have higher efficiency and consistently outperform both polycrystalline and thin film.
On a side note! If you’re in need of a reliable and high-performance portable solar panel, We strongly recommend the Jackery SolarSaga 100W Portable Solar Panel (Amazon Link).
With a high conversion efficiency and foldable design, this solar panel is easy to transport and set up, making it perfect for outdoor activities like camping, hiking, and RV trips.
The US solar cell technology used in this panel ensures that you get the most efficient and reliable solar charging possible.
There is also a 60W option that is more affordable (Amazon Link)
Solar panels can be rated or evaluated based on their efficiency, design, and temperature coefficient. Let’s look at each of these to see what they mean.
Efficiency
Solar panels produce energy through the process of a photovoltaic effect. Light from the sun or an artificial light source is converted into electricity by a solar panel through this process. Does all the light a solar panel absorbs get converted into electricity? Unfortunately for us, no.
Not all the light absorbed finds its way to your laptop as electricity. The photovoltaic process is not a 1-to-1 conversion. Only a small percentage of light gets converted into electricity.
A solar panel’s efficiency is a measure of how much light absorbed it converts into electricity. The highest efficiency achieved by a solar panel is 39.5%. This was achieved in a laboratory by sandwiching three layers of solar cells under concentrated light. We are not likely to see these solar panels reach the mainstream market anytime soon. Source
Commercially available solar panels have a much more modest efficiency. The most efficient type of solar panel you will find has a maximum efficiency of 24%. Which ones are those? Keep reading to find out.
Design
Solar panels are manufactured using different technologies. Solar panels like monocrystalline and polycrystalline are made from silicon. Then we have thin-film solar panels that are made from cadmium telluride, copper indium gallium selenide, and amorphous silicon.
Solar cells differ in their appearance based on what technology they are made from. Monocrystalline solar panels are made from a single crystal of silicon. They are a sleek black color. Polycrystalline solar panels are made from multiple pieces of silicon and have a blue color. Thin-film solar panels have a black or brown color.
Temperature coefficient
Solar panels have an inverse relationship to temperature. As the temperature rises in a solar panel, its efficiency decreases and it produces less energy. The heat reduces the effectiveness of a solar panel in generating electricity. This is known as the temperature coefficient of a solar panel.
Solar panel performance is evaluated based on Standard Test Conditions (STCs). This tells how much energy a solar panel will produce when:
- It’s exposed to a solar irradiance of 1000 watts per square meter,
- At a temperature of 25°C.
The inverse relationship between temperature and efficiency in a solar panel is stated as this. It is the percentage drop in efficiency with every 1°C increase over 25°C. Some solar panels have a higher temperature coefficient. In other words, the higher the temperature the less efficient they are.
Which Solar Panel Is Best And Why?
For most residential and commercial installations, monocrystalline solar panels are the recommended choice. They produce more energy per square foot, require fewer panels, and take up less space. This is primarily because they have a higher efficiency which allows them to generate more electricity.
What gives monocrystalline its edge over other solar panels? It is due largely because of how they are made.
Monocrystalline is made from crystalline silicon ingots. The ingots are cut into a single silicon wafer. This is crucially different from a polycrystalline solar cell. With polycrystalline, multiple shards of crystalline are used.
The single silicon wafer in a monocrystalline produces a solar cell that has a uniform black color. The darker color allows the solar cell to absorb more light compared to a polycrystalline solar cell that has a blue color. Darker colors absorb more light than bright colors.
Thin-film solar panels have lower efficiency and thus produce less energy. While they are also dark in color, they are made through a different manufacturing process from monocrystalline. Thin-film solar panels are typically the third choice for solar installations after monocrystalline and polycrystalline.
| SOLAR PANEL | EFFICIENCY |
|---|---|
| Monocrystalline | 18-22% |
| Polycrystalline | 15-18% |
| Thin film | 7-18% |
For more on this, we recommend that you check out our post Monocrystalline Vs Polycrystalline Vs Thin-film Solar Panels – Which Is Better!
What Type Of Solar Panel Lasts The Longest?
Solar panels have a lifespan of over 25 years. This applies to monocrystalline, and polycrystalline. Thin film solar panels last between 10 to 20 years.
Solar panel manufacturers warranty their solar panels for 25 years. The warranty guarantees a minimum performance over the lifespan of the solar panel. In reality, solar panels last longer than the 25 years they are warrantied for. They can last for up to 30 years or more. The oldest modern solar cell is over 60 years old and it still works. Source
Solar panel degradation
While a solar panel can last for decades, its performance does not stay the same from when it is first installed to when it reaches its end of life. Like all devices, it experiences wear and tear that gradually leads to a decline in its performance.
Unlike most devices, however, the decline in the performance of a solar panel is remarkably small. The dip in performance is called solar panel degradation and is quite minimal considering that a solar panel is an electrical device that is used every day.
Generally, a solar panel will experience a decline in performance of 0.5% per year. This means that at the end of 25 years, a solar panel will still produce as much as 88% of its potential output. Source
Also, check out our post on Which Type Of Energy Is Solar Energy? 4 Main Types !