solar panel efficiency

Most efficient solar panels: solar panel cell efficiency explained

Reading Time: 9 minutes

In the past years, solar technology has been making huge leaps and bounds towards higher solar cell efficiency, higher power output, and overall higher quality. For those looking for the most efficient solar panels for their solar energy system, the first thing you need to know is how to compare efficiency metrics for different manufacturer brands. Solar panel efficiency is one useful metric used to determine how much power a solar panel produces compared to other products.


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
  • SunPower, LG, and REC Solar make the most efficient solar panels
  • Start comparing solar quotes with high-efficiency equipment on the EnergySage Marketplace

In this article, we will dive into the following topics:

Solar panel efficiency: what you need to know

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.

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% efficiency in some cases (and almost reach 23 percent!), but the majority of photovoltaic panels available are not more than 20 percent efficiency. It’s worth noting that higher efficiency panels are a bit more expensive, but they will 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 in 2021 with the emergence of new technologies and manufacturing capabilities. 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. 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

2022 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.

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 5

Here are the top five best solar panel manufacturers ranked based on the highest efficiency solar panel they have to offer:

Top 5 solar manufacturers by efficiency rating

CompanyEfficiency ratingSolar cell technology  
SunPower22.8%
Monocrystalline
LG22.0%Monocrystalline
REC Solar21.7%Monocrystalline
CSUN21.2%Monocrystalline
Panasonic21.2%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 will often be the consumer favorite for anyone concerned with efficiency as a primal metric of interest. However, check out Exhibit 1 to learn about all the top brands and the most efficient solar panels you can get your hands on.

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 the 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 renewable 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 Solar 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:

  • Material – The type of material (monocrystalline silicon, polycrystalline silicon, cadmium telluride, thin-film 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
  • Reflection – If light is reflected away from a solar panel, it’s efficiency may be lowered. This is why the glass layer on top of silicon solar cells is so important.
  • Light wavelength/frequency – 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.
  • Temperature – 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.
  • Climate – Depending on where you live and the type of weather you have, 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. 
  • Shade  – 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.

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 a solar panel cell’s efficiency. 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 ManufacturerMinimum Efficiency (%)Maximum Efficiency (%)Average Efficiency (%)
Amerisolar14.75%17.01%15.97%
Astronergy18.10%19.10%18.62%
Axitec15.37%19.41%17.06%
BenQ Solar (AUO)15.50%18.30%17.19%
Boviet Solar16.50%17.50%16.98%
Canadian Solar15.88%19.91%17.88%
CertainTeed Solar17.20%19.90%19.06%
China Sunergy14.98%16.53%15.78%
ET Solar15.67%19.07%16.89%
First Solar17.00%18.30%17.65%
Grape Solar16.21%17.64%16.75%
Green Brilliance14.24%15.58%15.03%
Hansol14.97%18.05%16.49%
Hanwha19.30%20.30%19.80%
Hyundai16.20%19.40%18.49%
JA Solar15.80%20.40%18.05%
JinkoSolar18.67%20.38%19.57%
Kyocera14.75%16.11%15.42%
LG18.40%22.00%20.20%
LONGi18.20%20.90%19.59%
Mission Solar Energy18.05%19.35%18.73%
Neo Solar Power16.00%17.00%16.48%
Panasonic19.10%21.20%20.00%
Peimar Group16.60%19.36%17.84%
QCELLS17.10%20.60%19.20%
REC16.50%21.70%19.27%
Recom Solar16.00%19.05%17.31%
ReneSola14.90%16.90%15.91%
Renogy Solar15.30%18.50%17.30%
RGS Energy15.60%17.10%16.35%
Risen16.30%19.60%18.12%
S-Energy15.61%19.80%18.02%
Seraphim15.67%17.52%16.55%
Silfab17.60%19.70%18.86%
Solaria19.40%20.50%19.84%
Solartech Universal19.00%19.90%19.45%
SunPower16.50%22.80%20.73%
SunSpark Technology18.84%18.84%18.84%
Talesun Energy16.20%19.50%17.54%
Trina Solar17.20%19.90%18.69%
Upsolar16.50%19.40%17.92%
Vikram Solar16.52%17.55%17.03%

Why aren’t solar panels 100% efficient?


Solar panels do not convert light energy into electricity at 100% efficiency 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. Furthermore, the energy conversion process within the solar cells is not 100% efficient. As such, most solar panels have efficiency ratings around 20%.

Commonly asked questions about high efficiency solar panels

How efficient are solar panels in the real-world? 

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. 

Will solar panels ever reach 50 percent efficiency?

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-field. 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 in the future. 

How many solar panels does it take to power a house?

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 you need to power your house in our article

What is the most efficient type of solar panel?

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.

Compare your solar panel installation options on EnergySage

There are multiple variables to consider when seeking the best solar panels on the market. While certain panels will have higher efficiency ratings than others, investing in top-of-the-line solar equipment doesn’t always result in higher savings. The only way to find the “sweet spot” for your property is to evaluate quotes with varying equipment and financing offers.

For any homeowner in the early stages of solar shopping that would just like a ballpark estimate for an installation, try our Solar Calculator, which offers upfront cost and long-term savings estimates based on your location and roof type. For those looking to get quotes from local contractors today, check out our quote comparison platform.

core solar content

73 thoughts on “Most efficient solar panels: solar panel cell efficiency explained

  1. James H. Shanley

    The manufacturers efficiency ratings are not the end of the efficiency story. The DC energy must have storage capacity. The energy must then be changed to AC. Both of those processes reduce the overall efficiency. Likely it would be less than 10 percent.

    Reply
  2. Unleash Solar Mandurah

    I’m on my second solar system. The first 1.2kW system was installed in 2005 and I ended up replacing it 10 years later with a 6.6kw because it made financial sense to do so, mainly due to increased efficiency and the government incentives. This one will definitely pay for itself but the first one was a waste of money.

    Reply
  3. Chris

    Since I and many other will be referring back to this page and chart on Energy Sage in the future (for installation and upgrades to pre-installed systems), please include estimated wattage per panel and also dimensions of each panel as this information will help us determine how many panels we need and if we can actually fit that amount of panels. Thanks.

    Reply
    1. eng. Ali

      How many watts do you currently use?
      – A small home in a temperate climate might use something like 200 kwh per month, and a larger home in the south where air conditioners account for the largest portion of home energy usage might use 2,000 kWh or more. The average U.S. home uses about 900 kWh per month. So that’s 30 kWh per day or 1.25 kWh per hour.

      What is the effect of solar panel size?
      -Typical residential solar panel dimensions today are about 65 inches by 39 inches, or 5.4 feet by 3.25 feet, with some variation among manufacturers. SunPower panels are 61.3 inches by 41.2 inches.

      source: https://us.sunpower.com/how-many-solar-panels-do-you-need-panel-size-and-output-factors

      Reply
  4. Mick

    Great article. It surprises me that most solar panels are less than 20% efficiency. I’ve got the Solaria on my house – good to know it’s pretty up there on the list of efficiency. I knew when I bought it that it’s one of the best. Will probably look at investing in more solar panels that have a hire efficiency like Sunpower and LG. Cheers for the tips !

    Reply
  5. Dean Simmons

    Amount of power produced is not as cut and dry as directly comparing the efficiency numbers. Each increase in efficiency broadens the spectrum sensitivity range in sunlight. While you could have two panels with equal wattage, they wouldn’t gather the same amount of power if they had different efficiencies.
    Directly comparing monocrystalline (18-20-21%) to SunPower cells (21-23.5%), though your peak wattage may be Similar, SunPower cells gather almost 60%-80% More energy throughout the day because it has a broader sensitivity to the spectrum of light. (The effect is more pronounced as the sky becomes cloudy and overcast.

    Whereas poly or monocrystalline drops off in power fairly quickly in low/indirect/overcast sky’s, the newer technology will always remain more effective and produce more power under the same conditions.

    The effects are less pronounced if you have the space, such as on top a bus or a house, but where space is limited, such as on an RV or car, and to have more steady power production throughout the days, and if it’s not overly cost prohibitive, the newer panel will usually be a better choice.

    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *