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The Most Efficient Solar Panels of September 2023 - CNET

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You might not need the most efficient solar panels to reach your energy goals, but these models will wring the most electricity from the sun. Solar Pv

The Most Efficient Solar Panels of September 2023 - CNET

The most efficient solar panels available to residential customers come from two companies: SunPower and Canadian Solar. Both companies have solar panels with maximum efficiency ratings of 22.8%, but other companies are close behind. Prioritizing efficiency when you're shopping for solar panels may not make sense for most people, but if you want to set up the most efficient system, here's where to start.

Solar panels may all seem basically the same, but they're different in at least a few ways. One of those ways, efficiency rating, measures how much of the sun's energy a panel's solar cells turn into usable electricity. More efficient solar panels will generate more electricity than less efficient ones given the same amount of sunlight.

"If something is 20% efficient, that means that 20% of the energy in that sunlight reaching the solar panel gets turned into moving electrons," Daniel Ciolkosz, professor of agricultural and biological engineering at Pennsylvania State University, told CNET.

Choosing the best solar panels for your home is a game of balancing solar panel cost, function (like efficiency) and perhaps even aesthetics. Your choice is also limited by what your chosen solar installer actually offers.

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I've been writing about solar for CNET for the last two years, during which time I've read dozens of spec sheets and talked to dozens of industry experts about what matters for home installations. While ranking panels by their efficiency rating is a relatively straightforward task, I've also created the scoring methodologies for and ranked the best solar companies and best solar panels for CNET.

This list ranks the most efficient solar panels. Not only will we tell you which panels get top marks for turning the most sunlight into energy, we'll explain how much solar panel efficiency actually matters.

SunPower has long been the leader in solar panel efficiency, and its suite of panels has overall higher efficiency ratings than any other solar panel manufacturer. 

Canadian Solar's 445-watt model of its HiHero panel is the first solar panel to match SunPower's efficiency mark. With a temperature coefficient of -0.26%, it'll keep producing at a high level even when the temperature goes up.

At -0.24%, REC's Alpha Pure panel has the best temperature coefficient for panel power. It will lose less production at higher temperatures than other panels.

The Tiger Neo panel has a 22.27% efficiency rating and a temperature coefficient of -0.29%.

Panasonic's Evervolt panel, both the standard and the all-black versions, have an efficiency rating of 22.2%. They have a low temperature coefficient, too, at -0.26%.

Determining the highest solar panel efficiency is a pretty simple matter of tracking down manufacturer-provided data sheets and locating the efficiency numbers. Those numbers today are higher than in the not-too-distant past and keep creeping upward.

According to the Lawrence Berkeley National Laboratory's Tracking the Sun report, 2021 was the first year more than half the residential solar panels installed in the US had efficiency ratings above 20%. Ten years ago only 0.6% of those installed reached that mark. High-efficiency solar panels are more common than ever and becoming only more so.

If you're looking for the most efficient solar panel for your roof, here's how the most widely used brands on the market stack up.

Data accurate as of April 2023.

It depends on the solar panel. The most efficient solar panels listed above top 22% -- meaning they convert more than 22% of the available energy from sunlight into usable electricity. But not all solar panels hit that figure, and the ones you buy might fall well below it. Be sure to examine not just efficiency, but the whole expected output of your solar panel system for the price.

These are just the most efficient residential solar panels. Experimental technology and panels designed for commercial and utility-scale applications can be even more efficient.

The numbers listed above are obtained under controlled conditions in laboratory tests. In the real world there are plenty of factors that might cause you to receive less energy than a panel's efficiency rating would suggest. 

Sunlight: If the skies are hazy or cloudy, less sunlight will reach your panels and they'll produce less electricity than expected. 

Solar panel angle: You can't just point your solar panels up and expect them to work their best. There's an optimal angle and placement for your panels, and it depends largely on where you live.

Other electrical components: Power doesn't flow straight from the panels into your toaster. Some will be lost along the way through the inverter and other electrical devices. 

Temperature: Another factor affecting solar panels efficiency is their temperature. As solar panels get hot, they start to produce less energy, though not at the same rate. A solar panel's temperature coefficient measures how much worse its production gets for every degree Celsius (1.8 degrees Fahrenheit) it gets above 25C (77F).

Solar panels are installed at an angle to capture more of the sun's energy.

For example, at 26C (79F) a REC Alpha Pure would produce 0.24% less energy than at 25 degrees. At 29C (84F), it would lose just shy of 1% of its production.

There are three main types of solar panels, and each converts sunlight into power at a different rate. Here's a look at the three types:

All things being equal, it would make sense to choose a higher-efficiency solar panel over one with a lower rating. But high-efficiency solar panels typically cost more than lower rated ones, so making the best choice becomes a matter of balancing your financial goals with what your preferred installer offers and other considerations like brand and aesthetics.

"It's just one part of the equation," said Ciolkosz. "The bigger question for the end user is the economics and how it's paying off."

Is there a case where efficiency might be a worthwhile consideration?

"If you have one of those tiny homes on HGTV," said Tom Beresnyak, a Pennsylvania State University extension educator. 

If you're limited by available space for solar panels, you might want to squeeze out as much solar energy as possible from that space, though if your state allows it, a community solar subscription still might be a better choice financially, Beresnyak said.

No. But the panels listed here aren't the most efficient solar panels ever made, just commercially available ones marketed for homes. 

Research into solar cells (the energy-producing components that make up solar panels) has produced much higher efficiencies in the lab. The National Renewable Energy Laboratory tracks the highest efficiencies achieved in standardized lab conditions. The highest ever solar cell efficiency was 47.6%, recorded in June 2022.

Because there's no one-size-fits-all solar solution, there's no one-size-fits-all advice for choosing a solar company. The best approach is to get quotes from multiple installers before deciding. Choose the company that has offered you the best fit for your needs, you trust to do the work and has answered all your questions.

You should understand your energy usage before going solar and decide whether your goals are to completely replace that energy, save as much money as possible or achieve something else. From there, it's a matter of measuring competing quotes against your goals.

The Department of Energy recommends that you choose an installer with credentials from a respected third party, like the North American Board of Certified Energy Practitioners, which operates an online directory of certified installers that you can filter by state and certification.

Installers should definitely assess your roof condition because removing panels at a later date to replace a roof will be an additional cost. They should also be able to transparently answer questions about the systems design and why they're making their specific proposal.

"The installer can make a huge difference because the angle and the mount [are important for] maximizing what you have at that location -- a skilled installer is still going to be the real key in your long term production," Beresnyak said.

Read more: Want something smaller than a whole-home solar system? See our picks for the best portable solar panels and solar generators.

The panels on this list were chosen because they're some of the most commonly installed panels and are likely to appear on quotes for solar installations. If you're quoted for panels that don't appear on this list, you can check their efficiency rating and other specifications in the same way I did. Here's how.

Solar panel manufacturers publish data sheets for solar panels, which detail their dimensions, performance metrics and internal chemistry. If your solar company doesn't provide you with them, you can access them by clicking on the company name in the table above. (Many of the links lead to PDFs.) From there, it's a simple matter of comparing statistics.

The panels featured here are the most efficient offering from each of these companies. They may sell other panels that would appear higher on the list. In general, the higher a company appears on this list, the more efficient all of the solar panels they offer are.

Most of the solar panels installed today are made of either monocrystalline or polycrystalline cells. Monocrystalline solar panels are more efficient than their polycrystalline counterparts, though they're a bit more expensive. All the solar panels listed above use monocrystalline cells.

A third type of solar panel, thin-film solar panels, are less efficient than mono- and polycrystalline panels.

At the moment, the most efficient solar panels available on the residential market are made by SunPower and Canadian Solar. Other companies are catching up, however, and technology continues to improve.

In general, yes. While specific pricing information for solar panels isn't readily available, higher performance panels are typically more expensive. SunPower, which installs the most efficient panels, also started installing Qcells panels (the most frequently installed panels) to offer a more affordable option.

That means the panel is converting 20% of the energy from the sunlight that hits it into electricity. Of residential solar panels currently available, 20% would rank favorably. The most efficient solar panels on the market are more than 22% efficient.

On the residential market, the most efficient solar panels currently available are 22.8% efficient. In general, more efficient panels are possible. The National Renewable Energy Laboratory developed a solar cell with an efficiency of 39.5%, but don't expect to put it on your roof.

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