In the past years, solar technology has been making leaps and bounds towards higher solar cell efficiency, power output, and overall quality. Nowadays, solar panels have conversion efficiencies over 20 percent on average, compared to their previous average of less than 15 percent. They also now mostly come with a warranty of 10-25 years, helping you feel more confident in the longevity of your purchase. It is important to know what determines solar panel efficiency before making a purchase so your investment in solar can generate the most energy and ultimately save the most money on your electric bill.
Key takeaways about solar panel efficiency
- The most efficient solar panels available today are approximately 23 percent efficient.
- Solar panel efficiency is the percentage of incoming sunlight a single solar panel can convert into electricity.
- The most efficient solar cells developed by scientists offer 39.5 percent efficiency.
- SunPower, LG, and REC Solar make the most efficient solar panels available on the market.
- Start comparing solar quotes with high-efficiency equipment on the EnergySage Marketplace.
In this article:
- What is solar panel efficiency?
- How efficient are solar panels?
- How solar panel efficiency differs by product
- The most efficient solar panels
- What determines solar panel efficiency?
- How efficient are “high efficiency” solar panels?
- Common questions about solar panel efficiency
What is solar panel efficiency?
Solar panel efficiency is a measurement of a solar panel’s ability to convert sunlight into usable electricity. For example, if the sun shines on a high efficiency solar panel with a 20 percent rating, then 20 percent of the sun’s energy will be converted to solar energy. Given the same amount of sunlight shining for the same duration of time on two solar panels with different efficiency ratings, the more efficient panel will produce more electricity than the less efficient panel. Solar panel efficiency is determined by the production of electricity by solar cells, which is in turn influenced by the cells’ composition, electrical configuration, surrounding components, and more.
Solar cell efficiency
Overall solar panel efficiency is determined by the combined efficiency of each cell that makes up the panel. A wide variety of factors determine cell efficiency including the structure and type of material used (generally monocrystalline or polycrystalline).
How efficient are solar panels?
Today, most solar panels are between 15 percent and 20 percent efficient, with outliers on either side of the range. High efficiency solar panels can exceed 22 percent efficiency in some cases (and almost reach 23 percent!), but the majority of photovoltaic panels available are not more than 20 percent efficient. It’s worth noting that higher efficiency panels are a bit more expensive, but they can help you meet your energy needs, especially if you have a smaller roof and limited space.
If these efficiency rates seem a bit low to you at first glance, don’t be alarmed. The standard for efficiency is only rising as new technologies emerge and manufacturing capabilities improve. In fact, scientists have been able to achieve a record of 40 percent efficiency by using multi-junction cells optimized to capture different frequencies of light, although this is not currently attainable in commercially available panels. In the meantime however, current panel offerings provide more than enough usable electricity for most commercial and residential properties. Interested in learning more about solar panel efficiency? Read this article to see how it has changed over the years.
2023 high efficiency solar panel trends
Some Chinese companies are defying the “more efficient = more expensive” rule in 2022. High efficiency solar panels are entering the market from companies like LonGi, Canadian Solar, and Trina Solar that surpass the 20 percent efficiency rating, but cost less per watt as opposed to SunPower, LG and Panasonic panels. Solar is cheaper than ever without sacrificing efficiency ratings, which begs the question if U.S manufacturers will be able to maintain their pricing premiums.
What is the most efficient type of solar panel?
Monocrystalline solar panels are the most efficient type of panel with polycrystalline and thin-film solar panels being the other common types. However, for those looking to purchase solar panels, it is important to consider both the cost and overall efficiency in order to determine the type of panel that is best for you. It is important to note that there are different types of solar panels that vary in material they are made of. Their composition determines not only their cost but also how efficient they are.
Monocrystalline solar panel efficiency
Monocrystalline solar cells are the most efficient and can be used for residential properties as well as commercial installations. They are made from a single crystal of silicon which is highly efficient compared to panels with multiple fragments of silicon melted together. Their construction also allows them to take up less space. They can get expensive, however, so are not always the best choice for solar consumers with price as their biggest concern.
Polycrystalline solar panel efficiency
Unlike monocrystalline cells, polycrystalline solar cells are made from multiple silicon crystals melted together. They come at a lower price point but are ultimately less efficient and take up more space than monocrystalline silicon solar cells.
Thin-film solar panel efficiency
Thin film solar panels are lightweight, flexible, and inexpensive but are the least efficient type of solar panel. However, their versatility makes them a great choice for non-rooftop applications such as RVs and smaller appliances.
How solar panel efficiency differs by product
Given the same amount of sunlight shining for the same duration of time on two high efficiency solar panels with different efficiency ratings, the more efficient panel will have a higher power output than the less efficient panel. Solar cell efficiency is what determines the solar panel’s efficiency, which is influenced by composition, electrical configuration, surrounding components, and more. Solar cell efficiency equals the percentage of sunlight shining on each cell that is converted to electricity.
In practical terms, for two high efficiency solar panels of the same physical size, if one has a 21 percent efficiency rating and the other has a 14 percent efficiency rating, the 21 percent efficient panel will produce 50 percent more kilowatt-hours (kWh) of electricity under the same conditions as the 14 percent efficient panel. Thus, maximizing energy use and bill savings is heavily reliant on having top-tier solar panel efficiency.
Most efficient solar panels: the top five
Here are the top five best solar panel manufacturers ranked based on the highest efficiency solar panel they have to offer:
Top five solar manufacturers by efficiency rating
|Company||Efficiency rating||Solar cell technology|
|Panasonic||21.2%||Monocrystalline and amorphous silicon cell|
The most efficient solar panels on the market today have efficiency ratings as high as 22.8 percent, whereas the majority of panels range from 16 to 18 percent efficiency rating. SunPower high efficiency solar panels are known for being the most efficient solar panel brand available on the market. Though they will come with a higher price tag, SunPower/Maxeon will often be the consumer favorite for anyone concerned with efficiency as a primal metric of interest. Ultimately, you’ll need to consider various factors when choosing solar panels, including:
Maximum production or maximum offset
If your goal is to maximize the amount of electricity your system produces or want to ensure you buy the least amount of electricity from your utility, but the amount of roof space you have available to install solar panels is limited in size, you may choose to install higher efficiency solar panels. This will ensure you get the maximum power output from your solar panel system, and you will be producing the most clean energy possible.
Cost vs. value
Highly efficient solar panels tend to cost more than their less efficient counterparts due to the solar technology each type utilizes. You may want to analyze whether that upfront cost difference is justified by the increased savings achieved by generating more electricity over the lifespan of your solar energy system. Increased renewable energy production means you have to buy less power from your utility and in some states, may also generate higher SREC income. The EnergySage Marketplace makes it easy for you to easily compare your savings from solar panels that vary in their efficiency ratings and if their premium price is justified.
What determines solar panel efficiency?
There are several factors that determine how efficient a solar panel is. At its core, a solar panel cell’s efficiency is determined by how much incoming sunlight the cell can convert into usable electricity. But what factors into that end conversion rate? There are several items that photovoltaic (PV) cell researchers and manufacturers consider when designing and producing high efficiency solar technologies:
The type of semiconductor material (monocrystalline silicon, polycrystalline silicon, cadmium telluride, thin-film, perovskite etc.) impacts how light converts to electricity.
Wiring and busing
The organization of wires and “busbars” on a solar panel that actually capture and transfer electricity impacts efficiency
If light is reflected away from a solar panel, its efficiency may be lowered. The anti-reflexive coating on solar cells is vital to reduce light reflection, as is the quality of the glass layer on top of solar modules.
Light is made of particles called photons, which vibrate in a wide range of frequencies that make up all of the visible and invisible light emitted from the sun. When light hits the surface of a PV cell, some photons are reflected, some pass right through, and some are absorbed, depending on their frequency and wavelength. Some absorbed light may turn into heat, while the remaining photons that make it through have the right amount of energy to separate electrons from their atomic bonds, which produces an electric current. The larger the range of photons (infrared, ultraviolet, and the ‘visible range’) that a solar system can absorb, the higher the solar cell efficiency.
Positioning and angle
In order to capture the maximum amount of sunlight, proper solar panel installation and an optimized angle are key. Read our article about how solar panel angle impacts performance to learn more.
Higher temperatures will actually reduce energy output and lower efficiency, which is why some panels are designed specifically for warmer climates. Read our article about how the temperature impacts solar panel performance to learn about how to find the right angle.
Depending on where you live and the type of weather you experience, your solar panel efficiency can be positively or negatively impacted. For example, solar cells stop working when more than five centimeters of snow accumulate on the panel. Additionally, small decreases in efficiency can be found on particularly windy days.
Even a small shadow on a single panel can lower the system’s overall efficiency. While shade isn’t taken into account by manufacturers of panels themselves, it’s an important factor to consider and to mitigate if possible when you’re installing solar panels. Read our article about solar panels and shade to learn more.
There are other factors outside of the actual solar cells that impact efficiency that we won’t get into now. Those include, but aren’t limited to: solar inverter quality, wiring, installation quality, material durability over time, and more.
Additionally, factors like being able to absorb light on both sides of a cell (bifacial solar panels) and being able to absorb variable wavelengths of light (multijunction solar panels) change the efficiency equation for solar panels. All in all, there are a multitude of levers that scientists and researchers can pull when working on improving the efficiency of solar panels. In the end, it’s all about converting more incoming sunlight into electricity. Check out our article on different types of solar panels to learn more.
How solar panel efficiency is calculated
Solar panel efficiency can be calculated by dividing the total wattage of your system by the product of your solar panel’s square footage and the incident radiation flux, all multiplied by 100. Incident radiation flux refers to the amount of light that shines on the earth’s surface in your area. Standard solar panel testing conditions assume a 1,000 watt per square meter incident radiation flux.
For example, say you wanted to calculate the efficiency of your 400 watt solar panel. If your panel was 2 square meters, and you assume standard testing conditions, that is 2,000 watts. If you divide that number by 400 and multiply by 100, then a 20% efficiency rating is what you’re left with:
400 watt power output / (1,000 watt per square meter x 2 square meters) = 20% efficiency rating
You can also use our solar calculator to get an estimate of how much you can save with a solar panel installation.
How efficient are “high efficiency” solar panels? Efficiency comparison tables
The two tables below present different views of the solar panel efficiency characteristics of the leading manufacturers who sell solar panels in the United States. Most panel manufacturers produce several solar panel models which range in efficiency ratings. The leading brands in this category will be those that utilize high-efficiency solar cells such as LG and SunPower (who have battled back and forth for the world solar efficiency record) who are widely considered to be the top panel brand on the market for solar efficiency. However, it’s important to understand the difference between setting a maximum efficiency record and maintaining strong and consistent average solar energy efficiency ratings. Therefore, the following efficiency table breaks down the best ways to compare different solar panel options by module efficiency metrics.
Efficiency ratings of panel models by manufacturer
|Solar Panel Manufacturer||Minimum Efficiency (%)||Maximum Efficiency (%)||Average Efficiency (%)|
|BenQ Solar (AUO)||15.50%||18.30%||17.19%|
|Mission Solar Energy||18.05%||19.35%||18.73%|
|Neo Solar Power||16.00%||17.00%||16.48%|
Why aren’t solar panels 100% efficient?
Solar panels don’t convert sunlight into electricity with perfect efficiency mainly because they cannot absorb energy from the entire solar spectrum; there are certain wavelengths of light that solar panels cannot process, therefore they are reflected back off the solar panels or lost all together. What’s more, the energy conversion process within the solar cells is not 100% efficient.
Commonly asked questions about high efficiency solar panels (FAQs)
There are many factors that can affect the efficiency of your solar panels including weather, debris on your panel, or installation issues. That being said, all solar panels are tested under Standard Test Conditions to produce an accurate and standardized efficiency quote. Your panel’s temperature coefficient can help you understand how the efficiency may fluctuate depending on the temperature outside, or how the PV cells in your panel react to summer heat or winter’s cold.
Maybe! 47 percent efficiency has already been reached by a world record-breaking solar panel in a lab, and that same panel reached 40 percent efficiency in real life conditions. By combining six collectors, or photoactive layers, into a single panel, scientists at the National Renewable Energy Laboratory (NREL) were able to convert 40 percent of the sun’s energy into electricity in “single sun” conditions, or, conditions created to mimic the irradiance of one sun.
Each photovoltaic layer is manufactured to harness different wavelengths of energy, so the panel can convert energy from a higher percentage of the rays that hit its surface. This technology differs from traditional solar cell devices since there are 140 layers of the six collector materials used to make this high efficiency panel. A detailed description of the new technology was published in the journal Nature Energy. Researchers say that this technology can be fine-tuned to reach 50 percent efficiency. One thing is certain: there are plenty of solar technology advancements coming out in the near future.
The amount of solar panels it takes to power a house varies depending on how much energy you use, how big your house is, and the solar panels you have. That being said, the average house in the U.S uses 10,400 kWh of electricity annually- meaning that with 28-34 250 kilowatt (kW) panels (an average wattage for a solar panel), you could power your home entirely on the sun’s energy.
It is important for solar shoppers to do their due diligence in collecting all of the necessary information before going solar, such as how much electricity you consume and the sunlight hours your roof gets, to name a few. This way, you will know how many panels you need to power your home solely on solar energy.
Learn more about how many solar panels homeowners need on average in our article on the topic.
Currently, the most efficient solar panels available on the market are about 23 percent efficient. More specifically, SunPower’s high efficiency solar panels are recognized as the most efficient solar panels available, with a rating of 22.8 percent. Other manufacturers who make some of the most efficient solar panels include LG (22 percent) and REC Solar (21.7 percent).
Finding the right solar panel system is easy with EnergySage
Before you shop for a solar panel system, it is important to know how efficiency ratings are calculated, what it means to have an ‘efficient’ solar panel, and how to ensure your solar system is working as efficiently as the manufacturer says it will. However, it is also important to remember that although solar cell efficiency is an important factor to consider in your process, it is not the only relevant variable. Speak to one of our Energy Advisors through the EnergySage Marketplace to learn about everything you need to consider to go solar, from how to compare solar installers to what solar incentives are available to bring the cost of a solar array even lower.