In the past years, solar technology has been making leaps and bounds toward higher solar cell efficiency, power output, and overall quality. Today, most top solar panels have conversion efficiencies above 20%, compared to their previous average of less than 15%. They also now mostly come with a warranty of 10-25 years, helping you feel more confident in the longevity of your purchase. It’s important to know what determines solar panel efficiency 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 22.8% 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% efficiency (but these are not commercially available).
- SunPower, Canadian Solar, REC, and Panasonic 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?
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% rating, 20% of the sun’s energy will convert 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 cell efficiency
A solar panel’s efficiency is based on the efficiency of its solar cells, which depends on the cells’ composition, electrical configuration, surrounding components, and more. Solar cell efficiency refers to the percentage of sunlight shining on each cell that converts to electricity. The combined efficiency of each cell determines a solar panel’s overall efficiency. A wide variety of factors determine cell efficiency including the structure and type of silicon crystal (generally monocrystalline or polycrystalline).
How efficient are solar panels?
Today, most solar panels are between 17% and 20% efficient, with outliers on either side of the range. High-efficiency solar panels exceed 22% efficiency in some cases, while low-efficiency solar panels can be below 15% efficiency. Typically, higher-efficiency panels are more expensive, but they can help you meet your energy needs, especially if you have limited roof space or shading.
If these efficiency rates seem a bit low to you, don’t be alarmed. The standard for efficiency is only rising as new technologies emerge and manufacturing capabilities improve. Scientists achieved a record 40% efficiency by using multi-junction cells optimized to capture different frequencies of light, although this is not currently attainable in commercially available panels. Current panel offerings provide more than enough usable electricity for most commercial and residential properties.
2023 high-efficiency solar panel trends
Some companies are defying the “more efficient = more expensive” rule in 2023. For example, Jinko Solar, Trina Solar, and Canadian Solar all offer some solar panel models with efficiencies exceeding 20%, but come with lower price tags compared to high-efficiency brands like SunPower, REC, and Pansonic. While not yet widely available, Canadian Solar’s HiHero 445H-AG panels match SunPower’s industry record of 22.8% efficiency for residential panels.
|Brand||Average efficiency across models*||Price range**|
|SunPower||21.6%||$24,360.00 - $28,700.00|
|REC||19.6%||$17,500.00 - $24,220.00|
|Panasonic||21%||$18,270.00 - $24,150.00|
|Jinko||20.4%||$17,080.00 - $24,360.00|
|Trina Solar||18.3%||$16,730.00 - $19,530.00|
|Canadian Solar||18.3%||$16,100.00 - $20,300.00|
*Includes all actively quoted residential and commercial solar panel models on EnergySage.
**Prices reflect the average quoted price range of a 10 kW solar panel installation, including installation costs, after accounting for the 30% federal tax credit incentive.
What is the most efficient type of solar panel?
Monocrystalline solar panels are the most efficient type of panel; polycrystalline and thin-film solar panels are other common solar panel types that offer lower efficiency. For those looking to purchase solar panels, it’s important to consider both the cost and overall efficiency to determine the type of panel that’s best for you.
Monocrystalline solar panel efficiency
Monocrystalline solar cells are the most efficient and can be used for residential properties as well as commercial installations. These cells are composed of a single crystal of silicon which is highly efficient compared to cells with multiple fragments of silicon melted together. Their construction also allows them to take up less space. They can be expensive, so they made not be the best choice if cost is your biggest concern.
Polycrystalline solar panel efficiency
Unlike monocrystalline cells, polycrystalline solar cells are comprised of multiple silicon crystals melted together. They typically come with a lower price tag but are 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 or DIY 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.
In practical terms, for two high-efficiency solar panels of the same physical size, if one has a 21% efficiency rating and the other has a 14% efficiency rating, the 21% efficient panel will produce 50% more kilowatt-hours (kWh) of electricity under the same conditions as the 14% efficient panel. Thus, your electric bill savings with solar heavily rely on the efficiency of your solar panels.
Most efficient solar panels: the top 5
Here are the top 5 best solar panel brands ranked by the highest efficiency residential solar panel they offer in 2023:
Top 5 solar panel brands by efficiency rating
|SunPower||M Series 440 W||22.8%|
|Canadian solar||HiHero 445H-AG||22.8%|
|REC||Alpha Pure-R 430 W||22.3%|
|Panasonic||EverVolt HK Black Series 410 W||22.2%|
|Trina Solar||Vertex S+||21.8%|
Model: M Series 440 W
Image credit: SunPower
2. Canadian Solar
Model: HiHero 445H-AG
Image credit: Canadian Solar
Model: Alpha Pure-R 430 W
Image credit: REC
Model: EverVolt HK Black Series 410 W
Image credit: Panasonic
5. Trina Solar
Model: Vertex S+
Image credit: Trina Solar
The most efficient solar panels on the market today have efficiency ratings as high as 22.8%, whereas the majority of panels range from 17% to 20% efficiency rating. SunPower’s M-Series and X-Series panels (which Maxeon manufactures) are some of the most efficient available on the market. Though they come with a higher price tag, if you’re concerned about efficiency, SunPower/Maxeon is a great choice. 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 should choose higher efficiency solar panels. This way, you’ll maximize your solar panel system’s clean energy production.
Cost vs. value
Highly efficient solar panels tend to cost more than their less efficient counterparts due to the solar technology each type utilizes. However, the higher your panel efficiency, the more electricity you’ll produce and consume at home, meaning you won’t need to purchase much power from the grid. You may want to analyze whether the increased savings achieved by generating more electricity over the lifespan of your solar energy system with high-efficiency panels justifies the higher upfront cost.
What determines solar panel efficiency?
Several factors determine solar panel efficiency. A solar panel’s efficiency depends on how much incoming sunlight its cells can convert into usable electricity. So what factors impact that 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 much sunlight a solar cell converts to electricity.
Wiring and busing
The organization of wires and “busbars” on a solar panel that capture and transfer electricity impacts its efficiency
If light reflects 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
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 reduce energy output and reduce efficiency, which is why some panels are designed specifically for warmer climates. Read our article about how temperature impacts solar panel performance to learn about how to find the right angle.
Where you live and the type of weather you experience can impact your solar panels’ efficiency. For example, solar cells stop working when more than 5 centimeters of snow accumulate on the panel. Additionally, small decreases in efficiency can occur 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 solar panels themselves that impact efficiency, including solar inverter quality, wiring, installation quality, material durability over time, and more.
Additionally, factors like the ability to absorb light on both sides of a cell (bifacial solar panels) and the ability to absorb variable wavelengths of light (multijunction solar panels) change the efficiency equation for solar panels. Overall, there are many ways that scientists and researchers can improve the efficiency of solar panels: It’s all about converting more incoming sunlight into electricity. Check out our article on different types of solar panels to learn more.
How to calculate solar panel efficiency
You can calculate solar panel efficiency by dividing the total wattage of your system by the product of your solar panel’s square meters 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.
Let’s say you want to calculate the efficiency of your 400-watt solar panel. If your panel is 2 square meters and you assume a standard incident radiation flux of 1,000 watts per square meter, you get a product of 2,000 watts. Now divide that number by 400 and multiply the result by 100, giving you a 20% efficiency rating:
400 watt power output / (1,000 watts per square meter x 2 square meters) = 20% efficiency rating
You can also use our solar calculator to estimate how much you can save with a solar panel installation.
How efficient are high-efficiency solar panels?
Most panel manufacturers produce several solar panel models which range in efficiency ratings. The leading brands in this category are those that utilize high-efficiency solar cells such as SunPower, REC, Panasonic, and Canadian Solar, enabling them to offer the highest-efficiency panel models. However, it’s important to understand the difference between setting a maximum efficiency record and maintaining strong and consistent average solar energy efficiency ratings across all models. The following efficiency table breaks down efficiency by solar panel brand based on the minimum, average, and maximum efficiency across all residential and commercial panel offerings quoted through the EnergySage Marketplace:
Efficiency ratings of panel models by manufacturer
|Solar Panel Manufacturer||Minimum Efficiency (%)||Average Efficiency (%)||Maximum Efficiency (%)|
|LA Solar Group||20.56%||20.85%||21.28%|
|Mission Solar Energy||18.39%||18.95%||19.70%|
|United Renewable Energy (URE)||18.68%||19.93%||21.03%|
Why aren’t solar panels 100% efficient?
Solar panels don’t convert sunlight into electricity with perfect efficiency because they can’t absorb energy from the entire solar spectrum. There are certain wavelengths of light that solar panels can’t process, so they’re reflected off the solar panels or lost altogether. The energy conversion process within the solar cells also isn’t 100% efficient.
Frequently asked questions about high-efficiency solar panels
Many factors affect the efficiency of your solar panels including weather, debris on your panel, or installation issues. 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 its efficiency may fluctuate depending on the temperature outside, or how its PV cells will react to summer heat or a cold winter.
Maybe! A world record-breaking solar panel reached 47% efficiency in a lab and that same panel reached 40% efficiency in real-life conditions. By combining six collectors, or photoactive layers, into a single panel, scientists at the National Renewable Energy Laboratory (NREL) converted 40% of the sun’s energy into electricity in “single sun” conditions, or, conditions created to mimic the irradiance of the sun.
Manufacturers created each photovoltaic layer 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 because 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% 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. The average house in the U.S. uses 10,400 kWh of electricity annually, meaning with 17-21 400 kilowatt (kW) panels (a common wattage for a solar panel), you could power your home entirely on the sun’s energy.
You should do your due diligence and gather all of the necessary information before going solar, including how much electricity you consume and the sunlight hours your roof gets. 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% efficient. More specifically, SunPower and Canadian Solar’s high-efficiency solar panels are the most efficient solar panels available for residential systems, with a rating of 22.8%. Other manufacturers who make some of the most efficient solar panels include REC (22.3%) and Panasonic (22.2%).
Finding the right solar panel system is easy with EnergySage
Before you shop for a solar panel system, it’s worth understanding the importance of solar panel efficiency. But, you should also remember solar panel efficiency isn’t the only significant factor to consider in your solar panel decision. On the EnergySage Marketplace, you can compare solar panels based on multiple factors like power output, warranty, price, and more so you can go solar with confidence. Sign up for free today to get connected with your own Energy Advisor who can help guide you through the entire solar process.