How efficient are solar panels? Top brands compared in 2024
Solar technology has made leaps and bounds toward higher efficiency. Just five years ago, the average solar panel efficiency in quotes through EnergySage was 19%. In 2024, the average efficiency is about 21.4%, which translates to 10% more electricity produced per panel.
Within those averages, you'll find solar panels with a range of efficiency ratings. It might not surprise you that you'll usually
pay more for solar panels with greater efficiency. SunPower, one of the better-known solar panel brands, offers the most efficient and most expensive solar panels for homes at 22.8% efficiency. Other brands like REC, Panasonic, Maxeon, Jinko Solar, and Q CELLS aren't too far off with above 22% efficiency.
We'll help you decide if the highest-efficiency solar panels are worth it for you, and offer some advice on how you can keep your panels producing electricity as efficiently as possible.
KEY TAKEAWAYS ABOUT SOLAR PANEL EFFICIENCY
The most efficient solar panels available for homes today are 22.8% efficient.
Solar panel efficiency is the percentage of incoming sunlight that a single solar panel can convert into electricity.
What is solar panel efficiency?
Today, about 95% of solar panels quoted are between 19.7% and 21.6% efficient. Typically, higher-efficiency panels are more expensive, but they can be worth it depending on your energy needs and the configuration of your roof.
What are the most efficient solar panels in 2024?
SunPower offers the most efficient solar panels for homes today at 22.8% efficiency. They come with the highest price tag but can be worth it if your roof has limited space or a lot of shading. Otherwise, you may be better off choosing one of the other highly efficient, but more affordable solar panels on our list.
The most efficient solar panel brands, compared
Should you choose the most efficient solar panels?
It's important to choose efficient solar panels, but you don't always need to choose the most efficient model. Here are some scenarios when selecting the most efficient panels makes sense:
1. You want to maximize your solar production
You may want your system to produce as much electricity as possible. Or, you might want to buy the least amount of electricity from your utility but have limited roof space. In either of these cases, you should choose the highest-efficiency solar panel.
2. Higher-efficiency solar panels will save you money
Highly efficient solar panels tend to cost more than their less efficient counterparts. But, the higher your panel's efficiency, the more electricity you'll produce, and the more you'll save on your electric bills.
You need to calculate if the increased savings you achieve by generating more electricity over the lifespan of your solar energy system with high-efficiency panels justifies the higher upfront cost.
Let's consider two solar panel systems located in Massachusetts. Both have 20 solar panels of the same physical size. One system has SunPower's M-Series 440 W panels with 22.8% efficiency, while the other includes panels with 21% efficiency.
Solar savings with high-efficiency panels
*Based on an the Marketplace average cost per watt of $2.75/W.
**Based on EIA electricity data from April 2024.
In the example above, after considering your upfront costs and your 25-year electric bill savings, you'd save $1,423 more overall with the SunPower system over 25 years.
What's the most efficient type of solar panel?
The key thing to look for in a panel is the type of solar cells it uses. Monocrystalline solar cells are the ones you want. They're composed of a single crystal of silicon, which produces electricity very efficiently. Monocrystalline panels can be bifacial, meaning they absorb light on both sides of a cell, which increases efficiency. Some monocrystalline panels use multijunction technology, which means they can absorb different wavelengths of light, also increasing efficiency.
Solar panels can also have polycrystalline cells, which means they're comprised of multiple silicon crystals melted together. These panels typically come with a lower price tag but are less efficient than monocrystalline cells.
Thin film solar panels are lightweight, flexible, and inexpensive but are the least efficient panel technology. However, their versatility makes them great for non-rooftop or DIY applications, such as RVs and smaller appliances.
What determines solar panel efficiency?
We've gone over the basics of monocrystalline versus polycrystalline panels and the impact each material design has on efficiency, but there's more than just the structure of your panel that determines how well they can turn sunlight into electricity.
Solar cell reflection
If light reflects away from a solar panel, its efficiency will be lower. The anti-reflection coating on solar cells and the glass layer on top of solar panels reduce light reflection.
Solar cell wavelength/frequency
This one's science-heavy, but bear with us. Light is made of particles called photons, which vibrate in a wide range of requencies that make up all visible and invisible light emitted from the sun. When light hits the surface of a solar 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, producing an electric current. The larger the range of photons (infrared, Ultraviolet, and the "visible range") that a solar panel can absorb, the higher its efficiency.
Wiring and busing
The organization of wires and busbars (wires that connect solar cells) on a solar panel that capture and transfer electricity impacts its efficiency.
Inverter efficiency
Solar panel systems require inverters to convert the direct current (DC) electricity your solar panels generate into alternating current (AC) electricity, the type of electricity that powers home appliances. When your inverter makes this conversion, it loses some thermal energy. The higher the losses, the lower its efficiency.
Positioning and angle of solar panels
Solar makes sense for plenty of roofs, whether yours is south, west, or east-facing, flat or 45 degrees. However, you will lose some efficiency if your panels aren't directly south-facing or if their angle isn't quite right for your latitude. Learn more about
the best setup for your solar panels.
Shade
A slight shadow on a single panel can lower the system's efficiency. It's an essential factor for your installer to consider and mitigate. Read more about solar panels and shade.
Temperature
Solar panels become less efficient at high temperatures. For every degree above 25° C (or 77° F), your solar panel's electricity production will decrease by its temperature coefficient, which you can find on its spec sheet. For example, if your panel's temperature coefficient is 0.35%/°C, for every one-degree temperature increase above 25°C (77°F), its electricity production will decrease by 0.35%.
Climate
Where you live and the weather you experience can impact your solar panels' efficiency. Solar cells stop working when more than five centimeters of snow accumulate on the panel. Dust and dirt can have a similar impact. Small decreases in efficiency can also occur on particularly windy days.
How has solar panel efficiency changed over time?
The very first solar cells, invented in the 1800s, were less than 1% efficient––not nearly enough to make them a useful energy source. It wasn't until 1954 that Bell Labs invented the first useful silicon solar panel, which was about 6% efficient.
Since then, solar technology has evolved rapidly. Manufacturers have created prototype solar panels that are over 30% efficient, and homeowners on the EnergySage Marketplace regularly receive quotes for solar panels that are 20-22% efficient.
In coming years, we'll likely see solar panels get even more efficient. Researchers have achieved 47.1% efficiency using advanced cell structures. But, these super high-efficiency panels are typically made of more expensive materials that aren't cost-effective for mass adoption––at least not yet.
Frequently asked questions about high-efficiency solar panels
What factors can impact solar panel efficiency?
Many factors affect the efficiency of your solar panels, including weather, debris, and installation issues. All solar panels are tested under Standard Test Conditions (STC) to produce an accurate and standardized efficiency number.
How efficient will solar panels be in the future?
We don't know, but one thing is sure: Plenty of solar technology advancements are coming soon. A world record-breaking solar panel reached 47% efficiency in a lab. 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 sun's irradiance.
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 cells because 140 layers of the six collector materials are used to make this high-efficiency panel. Researchers say that this technology can even be fine-tuned to reach 50% efficiency.
How many solar panels does it take to power a house?