The search for the perfect solar panels can seem complicated and exhaustive since there are an overwhelming amount of options. You might have gotten multiple quotes from solar companies that include popular panel brands like SunPower or LG, but what makes these brands different from one another and the rest of their competitors?
LG, standing for Life’s Good, is a regular household name. LG engineers common household electronics from kitchen appliances to solar panels for consumers all over the world. SunPower, on the other hand, only manufactures solar products. Unless you’ve been researching solar panels or you’re in the solar industry, you might not have heard of SunPower.
The Bloomberg Tier 1 List is a compilation of qualifications for ‘bankability,’ or how likely a company is to be offered non-recourse debt financing by banks. Simply put, bankability is how profitable or stable a solar panel manufacturing company is. One qualification for bankability is zero-filed bankruptcies or insolvencies. Both SunPower and LG are financially-backed companies that follow specific guidelines to earn Bloomberg’s Tier 1 title.
Nonetheless, these manufacturers constantly compete against one other and standard panel brands. There are a number of distinctions between SunPower and LG panels that could impact a customer’s investment. Critical variables that shape project and investment outcome include, but are not limited to, panel materials, degradation rate, efficiency, warranties, and even the vetting process for installers.
Efficiency and Nominal Power
Solar panel manufacturers offer different efficiencies and wattage options that affect solar energy production. Solar panel efficiency is the portion of energy that can be converted into electricity via photovoltaics, or solar panels. The solar industry average for efficiency is 15-18%. Nominal power is the maximum power or wattage a solar system can generate. Nominal power can be measured in watts (W) or kilowatts (kW).
SunPower X-Series modules can achieve 22.8% efficiency, creating 60% more energy than other panels over 25 years. In terms of nominal power, X-Series modules range from 327 to 370 watts for residential projects.
Like SunPower, LG’s efficiency is above the industry average. LG’s panels can reach 21.1% efficiency. LG has lower wattage options than SunPower, ranging from 275 to 365 watts for residential projects.
Flexibility for the future
Because SunPower has the most efficient (and sustainable) solar modules on the market, the brand is able to provide more power for the same footprint. Under identical conditions, SunPower panels produce more energy than LG panels, so a customer might need more LG panels than SunPower on their roof to produce the same amount of electricity. Extra space on a roof from a SunPower system allows a homeowner to expand his or her system down the road to adapt to any lifestyle changes. A home’s energy consumption can increase from growing a family, working from home, building an addition, or driving an electric vehicle.
The more kilowatt-hours worth of power you can fit on your roof, the more power your system will produce, and the more money you’ll earn from solar incentives. This translates to a larger and quicker return on your investment. A customer could save and earn more money by choosing SunPower over LG because of variables such as efficiency rate and wattage options.
Solar Cell and Panel Materials
The type of materials in solar panels vary between brands. Most high-performing panels are monocrystalline, the most efficient solar panel type on the market. Monocrystalline panels contain the purest form of condensed silicon, unlike polycrystalline panels, which are made from multiple pieces of silicon. All solar panels have cells, a back sheet, and a frame.
What’s in a SunPower solar cell?
SunPower X-Series panels are monocrystalline and built with Maxeon cells, the highest rated solar cells in the industry. Maxeon technology incorporates a solid copper backing and a light-trapping surface, producing more power and adding more durability to your system.
Microfractures in solar panels
Conventional solar cells crack and shatter when pressure is applied because of their thin silicon wafer design with metal lines or ribbons pasted on the front. These cracks, known as microfractures, can disable standard panels from producing energy. Because of Maxeon’s copper backing, SunPower cells crack but stay intact and are still able to generate power. Combining the cells’ strength with high-quality glass and frames, SunPower panels are immune to microfractures in real-world conditions.
What’s in an LG solar cell?
LG’s monocrystalline cells include films of ethylene vinyl acetate (EVA), a durable material often used in shoes and life vests. LG uses new Cello technology in NeON 2 panels. Cello standing for Cell connection, Electrically, Low loss, Low stress, Optical absorption enhancement, has 12 wires that replace ribbons found in conventional panels and other LG models. Some LG NeON 2 cells are bifacial, meaning energy can be produced on both sides of the cell, but are only available in larger panel models.
Solar panels function differently over time depending on where they’re located. Like all electronics, solar modules are less efficient and productive in hot temperatures. The warmer the temperature, the hotter solar panels are on a roof so more electrons need space to move. This reduces the amount of voltage that a panel can generate, lowering its efficiency.
For every degree outside above 77 degrees Fahrenheit (F), electricity production will decline ever so slightly. SunPower’s temperature coefficient is -0.29 while LG’s is -0.30. This means that SunPower’s power output will decrease by 0.29% and LG’s by 0.30% for every degree over 77°F.
The industry standard for testing solar panels against heat involves placing them in a Temperature Cycling Chamber for 1,000 hours at 185°F and 85% humidity. This standard test examines whether a panel can perform well under typical warranties but does not guarantee long-term performance against real-world conditions.
SunPower’s temperature test examines panels at 13 times the industry standard. Under the test, X-Series panels are subjected to rapidly changing temperatures from -40°F to 185°F over several hours. This is designed to test their resiliency over two and a half decades. A conventional solar panel that is still up to industry standards can still fail under SunPower’s testing conditions due to its inability to expand and contract, causing the panels to break.
LG tests 4 times the industry standard, so the panels go through 4,000 hours at 190°F. To pass the test, LG panels must reach 18.8% efficiency at a 95% performance rate, also exceeding the industry standard. This is due to the EVA film used in LG cells, which helps the panel expand and contract during temperature changes.
What makes SunPower so resilient to temperature changes?
In order to form a solar panel or module, each cell must connect to one another. Conventional cells use metal ribbons to make this connection. However, these ribbons do not withstand expansion and contraction well, causing microfractures. SunPower’s thick copper backing also allows for built-in strain relief so panels can expand and contract during temperature fluctuations. Differing from conventional modules, SunPower uses a stamped metal interconnect that is soldered to the edges of the cell. This is also designed to lessen the effects of thermal stresses.
Factors like material durability and temperature coefficient impact various performance metrics like degradation. Degradation refers to the rate at which power is lost in a solar panel over its lifetime. Naturally, elements in nature weather panels over time. However, solar panel degradation can be extremely minimal, depending on the brand. Most manufacturers guarantee their modules to degrade no more than 0.7% each year for 25 years. After 25 years, conventional panels should produce about 80% of the energy they did at the time of installation.
All solar manufacturers test their products to ensure they can withstand elements in nature such as snow, wind, and fire. In New England, resiliency against hail matters. Standard testing involves evaluating panels against hailstones up to one inch in diameter falling at roughly 50 miles per hour. LG tests hailstones up to 28mm (1.10 inches), barely exceeding the industry standard, whereas SunPower tests their panels against golf ball-sized hail, about 42.67 mm (1.68 inches) in diameter.
SunPower and LG degradation rates
LG’s panels rank better than average, with NeON 2 degrading 0.6% per year and producing about 84% of Day 1 energy after 25 years. SunPower has the lowest degradation rate of any manufacturer, degrading only 0.25% per year and generating 92% of Day 1 production in Year 25. However, SunPower is backed up by field data and stress tests that suggest X-Series modules should have a total degradation well under 30% over 40 years. As a result, SunPower expects its modules have a ‘useful life’ of more than 40 years. A ‘useful life’ is a state at which panels produce at least 70% of their power from the time of installation. Over time, the differences in long term power output between SunPower and LG panels equate to significant savings for solar customers. Moreover, SunPower’s higher standards for hail can give Massachusetts residents greater peace of mind during the winter months.
A good warranty can make or break a customer’s investment from extreme weather, defective parts, or a bad installation. Depending on the vendor or contractor, enhanced warranties can be added on top of what the panel manufacturer automatically covers. All of our solar systems have a comprehensive 25-year warranty to ensure customers are protected head-to-toe.
Some pitfalls of standard panel warranties certainly degrade the customer experience. Under standard warranties, the customer often assumes the costs associated with replacing any defective panels. He or she is generally responsible for paying to ship new panels, packaging, shipping back defective panels, and sometimes even pay the manufacturer a testing fee if a defect is not found. On top of paying more than anticipated, the customer has a very short window to file a long written claim and present original physical proof of purchase.
With that being said, both SunPower and LG present sturdy warranties to their customers with some key differences. Warranties are generally composed of a product and installation warranty and a performance warranty.
What is a Solar Product Warranty?
An industry standard warranty protects customers for 10 years and typically covers defective parts throughout that time period. This form of warranty covers the integrity of the panels and protects customers against problems with manufacturing defects, environmental hazards, and premature wear and tear. However, some manufacturers do not cover their products or pay for any shipments if something breaks during installation.
SunPower’s 25/25/25 warranty includes a 25-year Product Warranty that covers the entire system, from the removal of defective parts to the installation of new ones. This includes the panels, microinverters, racking, and repair 100% replacement costs for 25 years.
Historically, LG always offered a 12-year Product Warranty but has been forced to compete with top brands like SunPower with more robust warranties. LG has recently begun including a 25-year warranty for modules. LG will repair or replace a module if it proves to be defective during the 25 year period. This warranty does not cover the removal or installation of new parts, shipping costs or if anything happens outside of the factory.
What is a Solar Performance Warranty?
The industry standard typically guarantees 80% of Day 1 performance after 25 years. A solid Performance Warranty can bring comfort to a solar customer knowing that his or her system will perform well in the long run.
SunPower’s 25/25/25 warranty offers covers performance and the amount of power generated. SunPower modules will produce at least 98% power for the first year and will decline by no more than 0.25% per year for the following 24 years. Ultimately, the power output following the end of the 25 year warranty period should be 92% of Day 1 production. LG warrants that the first five years of module power output will be no less than 95% of the labeled power output. During Year 6, LG anticipates a performance decline of 0.4% in each of the remaining 20 years. By Year 25, the output should be at least 87% of the power generated during Year 1.
Aesthetic Options and Panel Sizing
A number of studies indicate that aesthetics can be a deal-breaker for homeowners when buying solar panels. If solar panels or system design negatively impact the visual image of a customer’s home or landscape, the likelihood of that homeowner going solar diminishes.
Does solar panel size matter?
Even size is a changing variable among solar panel brands. It may seem insignificant, but the dimensions of a customer’s chosen solar panels determine the system’s layout on the roof. Chimneys, piping, and skylights can hinder the design of a clean solar array. Depending on the municipality in which the project is installed, different zoning bylaws can also impact a project’s design.
SunPower X-Series and LG NeON 2 (non-bifacial) are both 60-cell modules that vary slightly in dimensions.
This would likely matter most when a customer is interested in the
72-cell module LG NeON2 Bifacial solar panels. This means that fewer modules would fit on the same roof space as 60-cell X-Series or standard LG NeON panels, impacting the design and layout of the solar system.
Are all-black PV modules available?
According to an MIT study, customers with concern for aesthetic “prefer black solar panels with rounded corners and even surfaces.” All-black PV modules are available that include all-black cells, framing, and a back sheet. The design camouflages into other dark surfaces through its color and anti-reflective glass that reduces glare.
Both SunPower and LG have all-black modules, but they differ in maximum nominal wattage available. SunPower X-Series offers 327-350 W all-black panels while LG NeON 2 Black offers 300-320 W panels. So if a minimalist look is important to you, go with SunPower for its higher wattage options and power capabilities.
Vetting Process for Solar Dealers
All manufacturers have different protocols and standards regarding to whom they sell their products. Understanding the vendor or company that you purchase or lease your solar panels from is crucial in securing your savings.
SunPower only sells to certified solar companies like us, an Elite Dealer. The manufacturer carefully chooses dealers and installers nationwide that meet or exceed their selection process. SunPower prefers to work with companies who invest in their communities and have expert knowledge of local jurisdiction and permit regulations.
In contrast, LG isn’t too picky about who they do business with. LG sells to solar companies, but also to anyone who can obtain the “LG Pro Partner” title. Obtaining this title entails creating an account, taking a few short online trainings, and having the capital to buy the product. An LG Pro Partner does not need to be an established business nor have prior experience with solar. An ‘LG Pro’ can simply be a middleman without his or her own design, permitting, or installation teams, buying the product at cost and upselling to solar customers without contributing much or any expertise.
LG’s low standards for whom they sell to isn’t ideal for customers who want a reliable company. If a customer is set on having an LG system, then they should research the company they are doing business with. SunPower’s exclusivity to industry professionals is crucial for ensuring a superior project outcome.
Which Brand Will You Choose?
Choosing which solar brand is important in protecting your investment. There are reasons why someone choose either for their solar system, but SunPower blows LG out of the water with its panel durability, power output, inclusive warranties, and dealer vetting process.