SolarReviews scoring system to rank solar panel brands

SolarReviews is proud to announce the release of its 2024 Solar Panel Manufacturer Scoring System. The scoring system has been formulated after extensive discussion with industry leaders and offers a transparent and unbiased methodology for reviewing solar brands. 

The rankings are designed to provide homeowners insight into the likely quality and performance of solar panels over their full life. The term "full life" is key here, as solar panels are a long-term investment with a warrantied life of between 25 to 30 years.

Our team of solar experts reviewed 30 solar panel brands, narrowing it down to the top 10 best solar panels of 2024. 

Why was an expert rating system needed for solar panel brands?

After running a reviews website for the solar industry for many years, it was clear to SolarReviews experts that consumer reviews alone were not enough. 

Consumer reviews, while valuable, don’t always capture the whole picture. For example, homeowner reviews are typically written within the first year of a panel’s life and therefore don’t cover performance over time. Also, these reviews don't always consider the more complex side of solar. An expert rating system was needed to judge criteria not visible to consumers.

Our scoring methodology goes beyond looking at a solar brand’s current product line. Instead, we take a holistic approach that includes factors such as the company’s financial health, brand reliability, and availability.

Ranking factors

Below is a list of the criteria we used to score the solar panel companies, and the weights we assigned to each.

• Value (25%): Solar panels are a substantial investment, and their high upfront cost deters many homeowners from going solar. As such, we think solar panel cost is a significant factor to consider when rating solar panels.

• Module quality (20%): This is an assessment of the spec sheet performance of each company's top residential solar panel, specifically their efficiency rating and temperature coefficients. Panels that take up less space and perform more consistently in different climatic conditions will earn a higher score.

• Company financial performance (20%): This factor assesses the financial health of the solar panel manufacturer. This serves as the best possible indicator of whether the company will be around to honor any warranty claims that may arise.

• U.S. investment (15%): This factor assesses how committed each brand is to the U.S. market.

• Warranty (10%): Here, we look at both the product and performance warranty. The former reflects the module's reliability, while the latter tells you how panel performance will hold up with each passing year.

• Dealer network (10%): This reflects the availability of the brand among solar installers.

Let’s take a deeper dive into each category and see how we assigned scores for each.

1. Value - 25%

Points assigned for: Cost per watt

To ascertain the value of each solar panel brand, we assigned points based on the cost per watt of available solar modules at the time of scoring (December 2023). The lower the cost per watt, the higher the score. Cost is an important factor to homeowners when considering solar panels, so SolarReviews felt it crucial to include this criterion when ranking panels. 

We found that the solar panel brands offering the cheapest panels were nearly half the price of the most expensive. 

Highest value scores: JA Solar, Waaree, Heliene

Lowest value scores: CertainTeed, Panasonic, Maxeon

2. Module quality - 20%

Points assigned for: Panel efficiency; Temperature coefficient, PVEL Scorecard 

When judging module quality, we focus on the two most important items on the specifications sheet: panel efficiency and temperature coefficient.  We also reviewed if the brand was present on the 2022 or 2023 PVEL Scorecard.

Panel efficiency measures the amount of sunlight that gets converted into energy. Fewer high-efficiency panels are needed to meet homeowner’s energy needs. The temperature coefficient of Pmax tells us how well a panel will perform in real-world temperatures. The closer the temperature coefficient is to zero, the better. 

These two factors are not just meaningful on their own; they also speak to the solar panel’s overall production quality. Companies must employ advanced, highly automated manufacturing processes to achieve high-efficiency ratings and good temperature coefficients. 

The PVEL Scorecard is a third-party list that recognizes solar brands whose products have excelled in additional reliability and performance testing, further proving the quality of the brand’s panels. 

Highest scores for module quality: Maxeon, Panasonic, REC Group

Lowest scores for module quality: Mission Solar, Solaria, Aptos Solar

3. Financial visibility and strength - 20%

Points assigned for: Public listing; Availability of financial statements; Operating revenue and profitability

Solar panels are a unique product - they are designed to work for decades, and manufacturers guarantee a certain performance level for 25 years. Analyzing a company’s financial strength is the best way to determine how likely it is the brand will be around in the next 25 years to provide support. 

The first step is determining whether the company’s financials are visible and, therefore, easy to assess. Companies that publish their financial statements or are publicly traded get more points.

Next, we look at revenue. We assign points to companies based on the size of their overall revenue, as we deem larger manufacturers more likely to survive. Large manufacturers with revenue north of $2 billion earn the maximum number of points, while smaller players with under $100 million earn the least.

Finally, we look at profit. We assign extra points to companies that reported a net profit in the most recent financial year. The logic here is simple: profitable companies have the best chance of staying in business and expanding, while unprofitable companies have less rosy prospects.

Some of the brands we’ve rated are private or wholly-owned subsidiaries of larger groups that offer no visibility into their financial position. These companies were evaluated based on the information available from the parent company. 

Highest scores for company financial performance: Jinko Solar, Panasonic, Canadian Solar

Lowest scores for company financial performance: Aptos, Freedom Forever, SolarEver

4. U.S. investment - 15%

Points assigned for: Headquarters or offices in the U.S.; American manufacturing; Attendance at U.S. trade shows and events

Many consumers prioritize buying locally and supporting the local economy. To reflect this, we assigned more points to companies with global headquarters in the U.S., with fewer points if they only have offices here. We also awarded extra points to manufacturers with solar panel production facilities here in the U.S. and for recent attendance at major American trade shows and industry events.

The companies that score highest in this category are American-headquartered companies with local production facilities. However, some big foreign manufacturers score relatively high as well, having spent hundreds of millions of dollars to set up U.S. factories and strengthen their local marketing and support. Points were also awarded for companies that announced new manufacturing facilities in the U.S. that have not yet come online. 

Our logic here is that if a company has spent a lot of money building up its brand equity in the U.S, it is more likely to honor warranties to protect the reputation of its brand.

Highest scores for U.S. investment: Qcells, Solar4America, Silfab

Lowest scores U.S. investment: United Renewable Energy Co., Phono Solar, ZNShine

5. Warranty - 10%

Points assigned for: Product warranty length; 25-year performance warranty

The warranty is an important consideration when buying a product like solar panels since they are built to last for a quarter-century or longer. We’ve awarded higher points to the brands with the longest product warranty periods. 

For the performance warranty, we’ve also assigned the highest points to solar panels with the lowest degradation rates, meaning they will see the smallest output drop-offs over their warrantied lifetime. The panels that scored highest here indicate that they will produce 90% or higher of their rated output at the 25-year mark.

You may be wondering why we’ve decided to limit the warranty to just 10% of our score. The reason is simple: while warranty promises are useful, we believe that the company’s ability to honor the warranty is what really matters, a fact that is best reflected by its financial performance score.

Highest scores for warranty: Maxeon, Panasonic, REC Group

Lowest scores for warranty: Freedom Forever, Sunspark, Phono Solar

6. Dealer Network - 10%

Points assigned for: Share of residential installations

A manufacturer may offer great solar panels, but this is of little use if local dealers and installers don't carry their product. We allotted 10% of our score to reflect product availability and the installers that installed the brand. 

Dealer network quality was determined by reviewing data from California’s Distributed Generaiton Statistics database. 

Highest scores for dealer network: Qcells, Maxeon, Canadian Solar

Lowest scores for dealer network: Meyer Burger, Solar4America, Boviet Solar