Many well-known electronics brands have jumped on the solar panel bandwagon in the last few years, joining newcomers to the industry. When faced with so many choices, it can be tricky to figure out the best brands for solar panels.
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Given the investment involved and the fact you’ll be living with these panels for 25-30 years if you’re lucky, it’s smart to go with a well-established, reputable solar panel brand for a full rooftop solar array. If you’re just dipping your toes in the water of solar power, however, you might well be able to find a bargain on a single panel or two from a less established company.
Your needs will differ wildly depending on where you live, how hot it is, the amount of space you have, and other factors. Here, I offer some quick tips on how to choose the best solar panels for your needs and my top picks for the best solar panels available. If you do end up going the solar panel route, you’d do well to look into our list of the best lithium-ion batteries to store all that power too.
Runner up
The best solar panel brands
The following companies are known for making high-efficiency, quality solar panels:
- SunPower – makers of the most efficient solar panel at 22.8%, with an excellent warranty
- REC – an innovative company pushing the limits of home solar technology
- Panasonic – reputable, with a good warranty and high efficiency
- LG – affordable, high-efficiency, quality panels from a reputable company (but act fast!)
- Silfab – Canada-based makers of high-efficiency solar panels made in the U.S.
All of these companies currently offer a 25-year warranty for their high-efficiency solar panels. The current industry standard for panel materials warranties is just 10 years. I would strongly recommend against buying from a company that does not offer at least a 10-year warranty. Many companies now guarantee against equipment failures for 15 or 25 years.
Unfortunately, due to the cost of raw materials and uncertainty in the solar panel industry, LG announced in February 2022 that it would stop making solar panels by June 2022. It will still honor warranties and provide support to customers with LG solar panels, however. This is a big blow to the solar sector as LG consistently made high-efficiency, quality solar panels that were more affordable than SunPower’s panels.
If you consider yourself a bit more of a DIYer, your best bet may be one of the LG Panels through GoGreenSolar. While SunPower wins high marks for the quality of their solar panels from the team, their process tends to be dependent on having a vendor in your area and setting up consultations to have the panels installed for you. If you want beginning-to-end support in switching to solar power, SunPower should be your go-to. If you already know what you want and what you’re doing, a direct-to-consumer purchase like the above may better fit your needs.
SunPower solar panels
SunPower makes the most efficient monocrystalline solar panel currently available. With 22.8% efficiency, SunPower’s high-efficiency A-Series SPR-A425-G-AC Residential Solar Panels are a great choice for homeowners with limited space or who just want the best of the best.
SunPower’s panels are also affordable, when you factor in their high-efficiency. After all, you’ll need far fewer panels to produce the same amount of electricity as less efficient panels.
SunPower is also pretty ethical as solar companies go and offers an industry-leading 25-year performance warranty. This demonstrates the company’s confidence in their solar panels. Instead of the typical 80% performance warranty offered by most companies, SunPower are committed to a whopping 92% after 25 years. That means they are confident their panels will still be performing at almost full bore in more than two decades’ time.
SunPower panels have earned a bit of a reputation as being out of reach for most customers, pricewise. However, if you shop around and get a good installation team, your solar system using SunPower panels could cost you only marginally more than a much less efficient array.
All in all, if you have limited space and want the best solar panels available, from a company in the top 10 for ethical practices, SunPower is hard to beat. We also like them for their Flex range, ideal for smaller spaces such as RVs and mobile homes.
SunPower A-Series Residential Solar Panels
Highlights: The highest efficiency solar panels currently available, with 22.8% efficiency and power output of 400-425 W.
SunPower’s A-Series Residential AC Modules are rated at 400-425 Watts and boast SunPower® Maxeon® Gen 5 cells that are 65% larger than the company’s X-Series cells. These solar panels are intended for use with the SunPower Equinox™ system, a fully integrated solar solution designed, engineered and warranted by SunPower.
The panels offer the most powerful cells with the highest-efficiency in residential solar, meaning your panel makes more electricity per square foot than with any other commercially available solar. The SPR-A425-G-AC is 22.8% efficient, while the SPR-A415-G-AC and SPR-A400-G-AC models boast efficiency ratings of 22.3% and 21.5% respectively.
The temperature coefficient is -0.29%, and the operating temperature −40°F to +140°F (−40°C to +60°C), as per the full specification sheet. The maximum ambient temperature is 122°F (50°C).
Each panel contains 66 Monocrystalline Maxeon Gen 5 cells and has a factory-integrated microinverter which is 60% lighter than previous micronverters. They weigh 46.5 lbs (21.1 kg) and measure 72.2 by 40 inches.
When used with InvisiMount racking and InvisiMount accessories (UL 2703), the modules are Class A fire rated.
The one downside to SunPower’s A-Series panels is a relatively high temperature coefficient, compared to REC panels and a few others. This may mean they’re not necessarily the best choice for homeowners who live in very hot or cold climates. That said, even at a 0.19% drop in efficiency for every degree over 25 Celsius, the 22.8% efficient panels will be more efficient at 35 degrees Celsius than a 19.9% efficient panel with a lower temperature coefficient.
The A-Series is also a good choice if you live somewhere that gets lots of cloud cover, rain, and snow as the panels’ half-cut design will make the most of any sun that does make it through.
SunPower X-Series
Highlights: High-quality and efficient solar panels from one of the more ethical companies around. Cradle to Cradle Silver Certified and LEED qualifying!
SunPower’s X-Series solar panels are another great choice for home solar. These are the predecessor to the company’s A-Series and boast a slightly lower but still excellent efficiency rating of 21.5% for the SPR-X21-345 and 21% for the SPR-X21-335. The SPR-X22-360 has an efficiency of 22%.
Each module features 96 Monocrystalline Maxeon Gen III solar cells. The modules measure 61.3 inches by 41.2 inches and weigh 41 lbs (18.6 kg). The 335-BLK has an amost-all-black appearance while the 345 and 360 have more of a standard grid-like solar panel look.
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The 345 and 335, respectively, have rated power outputs of 345 W and 335 W and coefficients of –0.29%, as per the full specifications. The 360 (full specifications) also has a temperature coefficient of -0.29% and a rated power output of 360W. SunPower guarantees that power output to 95% for the first 5 years, then a maximum degradation of −0.4% annually until the panels are 25 years old.
Interestingly, the X-Series modules carry Cradle to Cradle Certified Silver status and are eligible for LEED points, while the A-Series doesn’t appear to carry this sustainability certification (yet).
SunPower 50 W and 110 W Flex
Highlights: Best solar panels for RVs, boats, mobile homes and smaller, unusual spaces.
If you’re tight on space and looking for the most efficient, high-quality solar panels around, consider the SunPower Flex series. These solar panels are ideal for RVs, boat, mobile homes, and other small areas where you need to work within tight space constraints.
The SunPower 50 W and 110 W Flex panels have a low profile and can bend up to 30 degrees, meaning it’s easier to get the right configuration even if you have to wrap them around a curved surface.
The panels are lightweight, great little performers in low light conditions, and are durable, easy to install, and adaptable. The Flex 50 W cost under a hundred bucks, making these a great first step into solar power.
As you might expect, given their flexibility, these panels cost quite a bit more, Watt for Watt, than the regular SunPower panels and other standard solar panels. If you need something robust that can perform great in harsh conditions, SunPower’s Flex panels are arguably your best option.
REC solar panels
REC is a long-standing (1996) European brand pushing the limits of solar panel technology. This innovative Norwegian company uses half-cut cell technology and a twin panel layout to maximize efficiency. Yes, this makes these panels some of the biggest available to homeowners, but they have black cells, frames, and backsheets, making them very inconspicuous on darker roofs. For more modern homes, REC panels may offer exactly the aesthetic you’re looking for.
Like SunPower, Panasonic, and LG, REC offers a 25-year warranty, which is far above the industry standard of a 10-year material warranty.
REC is vertically integrated, meaning the company designs and manufactures its own silicon wafers, cells, high-quality panels and full solar solutions. It has a reputation for high quality and few warranty claims and produces more than 1.5 GW of panel capacity annually.
Alpha Black REC 360AA
Highlights: A great choice of attractive, high-efficiency solar panel, especially if you live somewhere very hot or cold.
REC’s latest Alpha Black series of solar panels is also a fantastic choice for high-efficiency solar panels. These distinctive black solar panels are 20.3%, 20.6%, 20.9%, 21.2%, and 21.4% efficient, for the 355, 360, 365, 370, and 375 W respectively. The efficiencies are quite a bit lower than SunPower’s A-Series but still better than most solar panels.
Where the Alpha Black panels really shine, though, is if you live somewhere very hot or cold. That’s thanks to a much lower temperature coefficient (-0.26%) compared to SunPower (0.29%), meaning you’ll get better year-round electricity production with these REC panels.
In addition, each module features 120 half-cut cells with REC heterojunction cell technology and six strings of 20 cells in series. This means that even if a module is partially shaded for part of the day, it can still produce electricity.
The panels’ power output is guaranteed for 25 years. as per the full specification sheet. This incudes a maximum 2% decrease in the first year, followed by a 0.25% decrease annually until the panels are 25. This means that REC guarantees your panels will still be producing 92% of their initial output when they hit 25. This is far more generous than most solar panel warranties.
The modules measure 67.75 inches by 40 inches and weigh 43 lbs (19.5 kg). The frame is a black anodized aluminum, and this combined with the larger size makes for a very attractive solar installation, if you like that kind of thing.
The materials are warranted for 20 years. The panels are resilient against snow, wind, hail, salt spray, and fire.
Panasonic solar panels
Chances are you already own at least one Panasonic appliance. While more familiar for its microwaves and televisions, this company has also been active in the solar panel industry since the 1970s. Indeed, the company has set a few records for efficiency during this time, under the brand name Sanyo.
Panasonic panels are very efficient, at 22.2% for its best panels. These panels are another good choice for homeowners in very hot or cold climates as they have a temperature coefficient of just -0.26%, but are a little more affordable, smaller, and more traditional looking than REC’s panels.
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Again, Panasonic offers a robust 25-year warranty for its solar panels and prices them affordably. Panasonic announced in 2021 that it would start outsourcing its panel production. The idea is that this allows Panasonic to focus on providing the most efficient solar panels without the headaches of actually manufacturing them.
Panasonic is an innovator in the solar sector, known for bringing heterojunction technology to the fore. In 2021, Panasonic launched its new brand of EverVolt™ modules, which still use HJT but have larger half-cut cells (bringing the company up to date with the rest of the industry).
Panasonic EverVolt Series
Highlights: The Panasonic EverVolt Series offers excellent efficiency, a low degradation rate, guaranteed power output for 25 years, and an impressive temperature co-efficient – a top choice for hotter climates!
The most efficient of the panels, the EVPV410H boasts a 22.2% conversion rate, followed by the EVPV400H at 21.6%. The panels have a very low 0.25% annual degradation rate, with power guaranteed to 92% by a 25-year warranty. The Panasonic warranty also covers product, parts, and labor, assuming your panels are installed by a Panasonic Authorized, Premium, or Elite installer and registered within 60 days.
These panels have an industry-leading temperature co-efficient of just -0.26%, making them a fantastic choice for hotter climates. The half-cut cell technology makes these panels a good choice if your roof gets partial shade for some of the day.
Panasonic has also begun offering some of its modules with a darker black appearance, giving REC some serious competition. There are also some panels in the series that have a slightly different, strip-like look instead of the conventional grid pattern.
LG solar panels
If you act fast, LG is a great choice for solar panels for the home. The company makes some of the most efficient and affordable solar panels around and has a solid reputation for quality and customer service. Its call center is based in the U.S. and is very responsive and helpful.
Sadly, LG announced in February 2022 that it will close up shop for solar panels by the end of June 2022. This is due to increased raw material costs and an uncertain solar panel market. It’s possible that LG might reassess, given President Biden’s enactment of the Defense Production Act in early June 2022. For now, though, LG will still offer support to customers with existing LG solar panels and honor its warranties.
LG NeON R LG440AC-A6
Highlights: The highest efficiency LG panel with a huge 440 W output, excellent temperature coefficient, and great warranty.
The NeON R series is LG’s newer range of high-efficiency, premium-quality solar panels. The most powerful of the bunch is the LG NeON R LG440AC-A6 which boasts an output of 440 W and an efficiency rating of 22.1%.
The NeON® R has no electrodes on the front, making for a more modern, sleek aesthetic. Each panel weighs 45.2 lbs. (20.5 kg) and measures 75.2 inches by 41 inches by 1.6 inches (1,910mm x 1,042mm x 40mm)
These panels have a temperature coefficient of -0.29% and an annual degradation rate of just -0.25% in years 2-25 (1.5% in the first year). After 25 years, the LG NeON® R panel is guaranteed to at least 92.5% of its initial performance. The panels also come with a workmanship warranty of 25 years.
LG’s panels tend to be a bit pricier than other brands, but with the company shutting up shop on solar, you might be able to grab a bargain.
Other brands to consider for the best home solar panels
While SunPower, REC, Panasonic, and LG take top place for residential solar panels, there are plenty of other brands worth a look. All of the following brands make panels with at least 20% efficiency and a 25-year warranty:
| Brand | Efficiency | Temperature Coefficient | Great choice for |
| QCELLS | 21.4% | -0.34 | Dark roofs, long-term production, low-cost |
| Silfab | 21.4% | -0.36 | 25- or 30-year warranty, Made in North America |
| Jinko Solar | 21.33% | -0.35 | Eagle series, made in Jacksonville, Florida |
| Trina Solar | 20.4% | -0.36 | Founded in 1997, makes 500 W and 600 W panels |
| Winaico | 19.4% | -0.38 | Windy areas, environmental record |
The temperature coefficients of these panels are a lot higher, however. As such, you probably want to go with REC, Panasonic, AXITEC, SunPower, or LG if that’s a consideration where you live.
If you’re looking for solar panels made in North America, Silfab (a Canadian company) is a great choice. You might also want to look at the Eagle series of solar panels made by Jinko Solar in Florida. The company’s others panels continue to be made in China and Malaysia.
Trina Solar
Highlights: Longstanding, ethical, and reputable solar panel company making efficient and durable solar modules.
Trina Solar Energy was founded in 1997 and manufactures all its panels in China, though the company complies with European manufacturing laws and has high environmental standards. If you’re looking for a good mixture of solid ethics, efficiency, availability, and price, try Trina.
The Trina residential solar range includes two models: 365W DE06X.05(II) and 335W DD06M.05(II). These panels are resistant to salt, acid, sand, and ammonia and have been subject to a barrage of tests to confirm their robust nature and excellent performance.
The higher power module offers 355-380 W and is up to 20.6% efficient. They boast 132 half-cut monocrystalline cells and have a temperature coefficient of -0.34% (full specification). The modules measure 72.91 inches by 39.21 inches by 1.38 inches and weigh 43.4 lbs.
The 335W DD06M.05(II) (full specification) has 120 half-cut monocrystalline cells and a power output of 310-335W. These panels are up to 19.9% efficient and have a sleek black frame and streamlined aesthetic.
In 2021, Trina Solar increased its warranty from 10 years to 25 years for product and power. This warranty is only available in the U.S. and applies automatically – no registration required, and no restrictions based on who installs the modules.
The performance guarantee is for 97.5% by the end of year 1, followed by no more than a 0.6% degradation rate until the panels are 25 years old. This works out to a performance guarantee of 83.1% at 25 years.
The company carries a bunch of impressive certifications including ISO 14001: Environmental Management System and ISO14064: Greenhouse Gases Emissions Verification. The panels themselves come in recyclable packaging and are compatible with the PVCycle recycling process.
Jinko Solar
Highlights: Great for corporate social responsibility, high power output and good efficiency, with panels now made in America.
Jinko Solar is one of the world’s largest solar panel manufacturers and has been around since 2006. It has been a Tier 1 company since 2010 and predominantly manufactures panels in Vietnam and Malaysia. Jinko recently began making its Eagle series panels in Jacksonville, Florida, however, making this a great ‘made in America’ option for U.S. solar customers.
The Eagle G5 modules incorporate half-cut cells and Jinko’s Diamond Half Cell technology. By minimizing white space between cells, Jinko has produced modules with a power output up to a staggering 545 W. These panels are quite large and heavy though, weighing 64.82 lbs. each and measuring 89.53 inches by 44.65 in by 1.57 in.
These modules are Fire Type 1 rated with a tick frame, 3.2mm front side glass, and thick backsheet for added durability. The panels are certified to withstand humidity, heat, rain, salt spray, wind, hailstorms, and packed snow.
The half-cell bifacial Eagle 72HM G5b panels (full specification) offer 525-545 W and up to 21.13% efficiency. The temperature coefficient is -0.35%, however, making these a lesser choice for hotter climates.
Jinko used to be less generous about its warranties but has caught up with its competitors to offer a more robust warranty for product and power. For the Eagle 72HM G5b panels, Jinko offers a guarantee of no more than 1% degradation in the first year and no more than 0.4% each year thereafter until 30 years beyond the warranty start date. At the 30-year mark, then, your Jinko solar panels are guaranteed to have an Actual Power Output of no less than 87.4% of the Nominal Power Output.
Jinko Solar also offers a complete solar storage package that won the 2022 Green Builder Sustainable Product of the Year Award. The Eagle RS is a fully integrated DC-coupled 7.6kW/26.2kWh residential energy storage system. Adding this to your Jinko solar panels makes for a seamless step into home solar.
Winaico 330W to 340 W WSP-MX PERC
Highlights: Wind-resistant solar panels from one of the more ethical solar energy companies.
Nobody wants to invest a cool $20k on solar panels only to have them wrenched from the roof or mangled beyond recognition in a wind-storm. So, if you live in a particularly wind-prone area and are considering a solar array, look for panels with extremely strong framing and a reputation for standing up to a good whipping wind.
Winaico are a great choice for such conditions. Their panels were some of the first to pass an industry leading hail test, sport the HeatCap which helps protect against micro-cracks that impact performance, and they have an extremely tough and durable design with water drainage channels to help reduce dirt and dust accumulation.
This family-run Taiwanese company is unique among competitors in that they don’t distribute panels through wholesalers. Instead, they provide panels direct to installers, solar technicians, and project managers, which can both help to reduce your costs and ensure a more direct relationship between the company and the end user.
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Winaico solar panels are tested to German TUV standards and were recently awarded a 2018 Top PV brand seal in Germany for quality and longevity. The company integrated PERC (passive emitter rear cell) technology earlier than most companies and makes very efficient monocrystalline cells, including the 330W to 340 W WSP-MX PERC.
The WSP-MX series uses high-grade P-type mono PERC cells with 5 busbars to deliver up to 19.4% efficiency (with the 340 W model) as per the full specification sheet. The panels have a temperature coefficient of -0.38%, though, which isn’t great.
They incorporate the familiar high-strength Winaico frames and drainage features, and come with a 15-year product warranty and a 25-year performance warranty. The average linear degradation is 0.7% annually, with a performance warranty guaranteeing 80.2% at the 25-year mark.
Winaico claims to have had only 16 recorded panel failures across more than 250,000 panels distributed in Australia over the last 7 years.
Winaico also advocates for Extended Producer Responsibility (EPR) and strive to reduce energy and water usage throughout the manufacturing process. They pay attention to environmental protection across the whole life-cycle of the solar panel and work with recycling partners to help ensure the products are recycled in compliance with the WEEE directive (Waste of Electrical and Electronic Equipment). Winaico’s environmental management system is also certified to ISO 14001 and they put out an annual Corporate Social Responsibility report.
Silfab Solar
Highlights: The most efficient solar panels manufactured in the U.S., with a sleek black look and potential tax credits through the Buy America Act.
Silfab is headquartered in Canada but has factories in both Canada and America. The company makes the most efficient solar panels manufactured exclusively in America, meaning that some Silfab solar panels comply with the Buy American Act (BAA). This opens up additional financial incentives for commercial and residential solar projects and means there are customer service representative in America and Canada to help if necessary.
Silfab used to be a commercial and residential OEM manufacturer for other Tier 1 companies. In the last decade, however, Silfab branched out to design, engineer, and manufacture its own premium brand of high-efficiency solar panels.
Silfab offers value for money and an American-made product with a lower carbon footprint than most solar panels. The current range includes its Prime, Elite, and Commercial series of solar panels, with the Elite series offering efficiencies as high as 21.4%.
Silfab uses advanced back-contact technology to reduce the presence of metal on the front of the panels. This not only allows for a sleeker aesthetic, it also minimizes conductive losses, mechanical stress and shading. This means greater reliability, performance, and efficiency overall.
The most efficient SIL-380 BK panels (full specification) measure 70.67 in x 38.98 in x 1.5 in and weigh 41.9 lbs. These panels boast 66 high-efficiency back contact mono-PERC c-Si cells per panel.
The main downside to Silfab’s panels is a fairly high temperature coefficient of -0.377 %. These panels are probably best suited, then, for homeowners in areas that don’t get super hot.
Silfab offers a module product workmanship warranty for 25 years, and a linear power performance guarantee for an impressive 30 years. This comprises a guarantee of at least 97.1% performance by the end of the 1st year, followed by at least 91.6% at 12 years, 85.1% at 25 years, and 82.6% at 30 years. That’s about a 0.58% annual degradation rate over 30 years.
Hanwha Q CELLS Q.PEAK DUO G10
Highlights: High-quality solar panels made in the U.S. with a solid warranty and performance warranty and half-cell technology good for shadier spots.
The Q Peak DUO G10 is the latest generation of solar panel produced by Hanwha Q Cells. Made in Georgia, U.S., these panels offer up to 360-380 W and have a generous 25-year performance and product warranty. The performance warranty guarantees at least 98% of nominal power during the first year and a 0.5% maximum degradation rate thereafter, providing at least 93.5% of nominal power up to 10 years, and at least 86 % of nominal power up to 25 years.
With 120 half-cut monocrystalline PERC cells, these panels are a good option for partially shaded areas. They’re also certified for high snow (5400 Pa) and wind loads (4000 Pa) and have a temperature coefficient of -0.34%. each panel measures 67.6 × 41.2 × 1.26 in and weighs 43.9 lbs.
Confusingly, the Q Cells website states an efficiency of 21.5% for these panels, but the specification sheet states up to 21.2% under standard test conditions. Either way, this is an excellent efficiency rating.
Hanwha Group is one of the world’s largest and most well-regarded photovoltaic manufacturers. It is a FORTUNE Global 500 firm and a Top 8 business enterprise in South Korea, has been around since the 1950s, and started making solar panels in 2011. Hanwha is also a consistent Tier 1 solar panel manufacturer, meaning it’s likely to be around to honor those warranties.
In 2012, Hanwha bought out the German company Q-Cells. Thereafter, it quickly became one of the best brands of solar panels around. Interestingly, Hanwha Q-Cells are currently engage in legal action against Jinko Solar, REC Group and Longi alleging patent infringements.
Mission Solar
Highlights: Highlights: Made-in-America solar panels, great for larger rooftops in the northern states, and very affordable!
Mission Solar offers made-in-America residential solar panels in several sizes and with a few different color options. The company’s most efficient module currently is the MSE330SR8K which is rated up to 19.53% efficient with a temperature coefficient of -0.375%.
This module has a sleek all-black design and fairly compact size at 65.98 in. x 39.68 in. x 1.58 in. Each panel weighs 44 lbs. and features 60 P-type monocrystalline cells (6×10) with 5 busbars (full specification)
Mission Solar modules are very robust and are resistant to 5,400 Pa front load and 3,600 Pa back load. These panels make the California Energy Commission’s approved list, which means they’re more likely to qualify for solar rebate programs across the U.S.
Mission Solar guarantees no more than 3% panel degradation at the 1-year mark, and a guaranteed capacity of 90.7% at 10 years and 80.2% at the 25-year mark. This is a higher degradation rate than most of the companies on our list, but still very good, especially given that Mission Solar panels are so affordable.
Mission Solar modules are made in San Antonio, Texas, and are some of the cheapest solar panels around. Don’t let that fool you, though. These are still quality solar panels and a great choice if you don’t mind a slightly lower efficiency rate, and a slightly higher temperature coefficient. Ironically, given they’re built in Texas, these panels are better suited for customers in Alaska, Wisconsin, Maine, or Washington State, rather than hotter southern climes.
AXITEC has been making solar panels since 2001 and is based in New Jersey, with warehousing in California. This makes AXITEC a great choice if you want solar panels fast!
The company controls its entire manufacturing chain, through to sales and service, which is always helpful for more complex electronics and home appliances. AXITEC manufactures its panels in Germany and offers panels up to 21.48% efficient. The panels are also very affordable and have excellent temperature coefficients.
The Axitec AC-555MH/144V is the company’s most efficient solar panel, with a power output of 555 W and an efficiency of 21.48%. The panels comprise 144 monocrystalline high-efficiency cells and have a temperature coefficient of -0.35% (full specification).
Each panel measures 2278 x 1134 x 35 mm and weighs 28.5 kg. The panels have a design load of (pressure/suction) 3600 Pa / 1600 Pa and a test load (pressure/suction) of 5400 Pa / 2400 Pa.
Axitec offers a 15 years manufacturer‘s guarantee to 90% of the nominal performance, and a 25 years manufacturer‘s guarantee to 85% of the nominal performance.
Key Considerations when Buying Solar Panels
Solar Panel Efficiency
Solar panel efficiency is often touted as the be all and end all when choosing a solar array. The truth is, though, that unless you’re very tight on space, you may be better off going for a slightly cheaper model of solar panel that is a little less efficient and just takes up a dash more space. After all, a 300-Watt panel will still produce 300 Watts, regardless of how big or small it is. If you have a small roof space, however, choosing more efficient solar panels gets you the maximal solar output for your space.
Understanding solar panel efficiency can be a bit confusing, so let’s break it down. Imagine two solar panels that are the same size. One is 20% efficient and the other is 16% efficient. That’s a difference of 4% between the two, which is a quarter (or 25%) of the lower efficiency solar panel. So, under the same conditions, the more efficient panel will produce 25% more electricity than the less efficient panel.
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Need another example? Take two panels that are 21% efficient and 14% efficient. That’s a 7% difference in efficiency, or half of the lower efficiency panel’s efficiency rating. This means that the more efficient panel produces 50% more kilowatt hours given the same conditions.
In a small space, a 25-50% improvement in efficiency can really make a difference to your electricity bill!
So, which solar panels are most efficient? The top solar panels for efficiency, topping 22%, are:
- SunPower – SPR-A425-G-AC is 22.8% efficient
- SunPower – SPR-A415-G-AC is 22.3%
- Panasonic – EVPV410H is 22.2% efficient
- LG – NeON R LG440AC-A6 is 22.1% efficient.
Remember, though, that these efficiencies are at ideal conditions, for the first few years of a panel’s life. As panels get older, or at much hotter temperatures, or in partial shade, different panels fare better or worse than others.
Solar Panel Efficiency in Hot Climates and Lifelong Solar Panel Efficiency
If you live in a more northern state, or are way up in Alaska, you don’t need to pay much, if any, attention to temperature coefficients. For anyone in the south, though, this may be a major factor in your decision-making process.
Multi and mono cell solar panels tend to lose 0.38% to 0.42% efficiency for every degree Celsius increase. This drop in efficiency is called the temperature coefficient. On very hot days with little wind, your solar panels may well produce 20% less electricity than under ideal conditions.
Most solar panels are rated for efficiency based on a temperature of 25 degrees Celsius or 77 degrees Fahrenheit. So, if your solar panels has a temperature coefficient of -0.3%, the panel’s electricity output falls by 0.3% with a one degree increase in temperature to 26 degrees Celsius. If it’s 35 degrees Celsius (95 degrees Fahrenheit) on your roof, that panel will produce 3% less electricity.
The temperature of a flat black roof on a spring day can easily top 25 degrees Celsius, and in summer months the drop in electricity output can be significant with less efficient models. If this sounds like your situation, you’ll want a solar array with a low temperature coefficient.
Panasonic’s N-type silicon cells and REC’s Alpha Black series are great performers at high temperatures, making them a good option for more southern states. They lose less than 0.26% efficiency per degree Celsius increase, which is the best temperature coefficient around today.
Other solar panels that lose little efficiency at high temperatures include the Solartech Universal panels, with a temperature coefficient of -0.26% (like Panasonic’s and REC’s), SunPower (-0.29% temp. coefficient), and LG (-0.3%).
Premium N-type solar panels cost a little more per Watt but are vastly more efficient than other models. They are also far better performers in hot climates, and they suffer little light-induced degradation (LID), meaning that they remain efficient even after a couple of decades.
Best Solar Panels for Partially Shady Areas
If your roof only gets full sun for part of the day, you might think that solar panels won’t work for you. Happily, clever engineers have found a solution: split modules with half-cut cells.
These panels, which have a junction box in the center of the module, essentially provide two halves of a full panel that work in tandem when the sun is full but don’t rely on the other half when shadier conditions prevail.
These half-cut panels also have increased performance because the current collectors (bus bars) can be thinner (because each cell produces the same voltage, just at half the current). Thinner bus bars means less resistance and energy loss, lower temperatures (and greater efficiency) and a greater cell surface area.
Most major solar providers now offer split panels, but REC’s half-cut panels were some of the first and are still some of the best.
Best Solar Panels for Wind Prone Areas
Nobody wants to invest a cool $20k on solar panels only to have them wrenched from the roof or mangled beyond recognition in a wind-storm. So, if you live in a particularly wind-prone area and are considering a solar array, look for panels with extremely strong framing and a reputation for standing up to a good whipping wind.
Some good options include Winaico and Q.Peak DUO panels from QCELLS. Winaico’s panels have an impressive reputation for durability and the company has led the way for years on durability and innovation to make panels more resistant to wind, hail, and other weather extremes.
Cost per Watt
If you’re staring at two solar panels that look pretty much the same, with a similar efficiency rating, warranty, and temperature coefficient, you might want to consider the cost per Watt as a tie-breaker.
Full-sized panels typically provide 275-400 Watts, and most come in at less than a dollar per Watt. For the most efficient and best performing solar panels, such as those made by SunPower and LG, using N-type monocrystalline silicon cells, the cost may be significantly higher. So, be sure to compare like for like.
Warranty and Service Record
If you choose well and are lucky, your shiny new solar panel array may be with you for the next 25 or even 30 years. The best companies around will offer a warranty that covers those panels for at least two decades and will still be around to make good on any warranty should you need to make use of it. After all, what good is a 30-year warranty from a fly-by-night company that can’t or won’t honor it.
Thankfully, several of the best solar panels around are made by companies with a good track record for longevity and service, including LG and Panasonic.
A materials or equipment warranty protects your solar panels against failures that arise as a result of environmental factors or defects. Typically, LG, Panasonic, SunPower, Q CELLS, and a handful of other companies offer a 25-year warranty on their solar panels. REC’s warranty has recently been extended to cover 25 years for some panels. Always confirm warranty conditions before buying, if this is a key concern for you.
You may see the term ‘Tier 1’ in some sales and marketing materials. This rating was developed by Bloomberg New Energy Finance Corporation as a way to rate the financial stability of a solar panel manufacturer. Tier 1 has little, if any, bearing on the performance or quality of a solar panel, just the company that makes it. Most of the big names in solar panels are Tier 1 companies, making other considerations far more pressing. Interestingly, Panasonic slipped out of Tier 1 status in the first quarter of 2020, which may be related to the Japanese company cutting ties with Tesla (a relationship that seemed to be financially damaging to Panasonic).
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If you have concerns over the status of a company from whom you’re considering buying solar panels, check out their warranty small print. Ideally, a warranty will be backed by a third-party. This means that even if the original company can’t support the coverage (if they become insolvent, say), your panels will stull be under warranty by the third-party, making this a low-risk option.
Ethical Solar Panels – Eco-Friendly, Low-Toxicity Solar Panels
Finally, there’s no getting around the fact that producing solar panels is an energy intensive business. Though claims that it takes more energy to produce and ship these panels than will ever be produced by the panels themselves seem rather spurious, solar panels have a few other environmental downsides too, mostly related to their composition.
Many panels now rely on rare earth metals such as gallium and iridium, which poses problems related to ethical mining. Some older panels contain toxic heavy metals such as cadmium and lead, which can leach into groundwater and pose a health hazard for production workers, end users, and those disposing of panels at end of life. Speaking of which, solar panels are notoriously difficult to recycle because they contain such a complex mix of materials.
In the U.S., dedicated solar panel recycling facilities have only just begun popping up, following the lead of European countries where there’s a directive mandating proper disposal of these products. No such directive or regulation exists federally in the U.S.
Our top picks for the best solar panels takes into account both the companies’ eco-friendliness and general ethics as well as performance, price, and availability. After all, it’s not particularly eco-friendly or ethical to choose a lesser quality product that only lasts a few years before it needs scrapping and replacing.
Solar Patio?
Finally, if you really want to show off your eco-chops, think about installing solar panels on your driveway, patio, courtyard, or balcony. Platio, a Budapest-based company, shook up the industry in 2017 with their innovative space-saving, attractive and low maintenance Platio solar paving made from recycled plastic and glass. Easier to look after than roof mounted systems, the Platio system is a great choice for soaking up solar power during the day and then recharging your car when you get home at night.