In the movie Bull Durham there is a scene between Kevin Costner’s character “Crash” and Tim Robbins’ character “Nuke” wherein Crash is chastising Nuke:

Crash: “You’re wasting your whole life away!”

Nuke: “I ain’t wasting nothing away! I got a Porsche already — a 911 with a quadraphonic Blaupunkt!”

Crash: “Jeez, you don’t need a quadraphonic Blaupunkt. What you need is a curve ball! In the Show, everybody can hit heat!”

That scene reminds us at Solar Watchdog about the dangers of lingo used by shifty salespeople in the solar industry. What in the world is a quadrophonic Blaupunkt? Similarly, what in the world is a Tier One solar panel?

Now, consumers are going to be hard-pressed to come across a salesperson who doesn’t say “we are going to install a Tier One solar panel for your home”. They all do. All of them. Without fail. First of all, lots of companies just flat out say that when they aren’t. In other words, they lie. Second of all, a solar panel qualifying as a Tier One panel is not the end-all, be-all that shady salespeople make it out to be.

Solar Watchdog has spoken with thousands of customers, and we would be shocked if we could name more than ten people who could state what exactly a Tier One panel actually is. Most consumers aren’t sophisticated purchasers enough to know what questions to ask. We will finish with an educational discussion on what is a Tier One panel; but, the most important thing to know is, other than price, there are three (3) factors on which to judge solar panel quality: (1) efficiency; (2) temperature coefficient; and (3) warranties. Let’s touch upon those briefly.


Efficiency is the measurement of how effectively a module (i.e., a solar panel) converts photons (also known as sunlight particles) into (direct current) electricity. The higher the efficiency, the better. Consumers should be sure to inquire about not only what manufacturer of panels is being sold to them, but what specific model, as even these top-of-the-line panels have varying efficiencies, depending on the model. If you will read through Solar Watchdog’s website, specifically in the tab labeled Watchdog Resources, under Industry Secrets, you will find a brief discussion on the 3-day period each homeowner has to cancel a solar system purchase (see Tax Credits versus Tax Rebates). Use those three days wisely. Solar Watchdog only recommends to consumers companies that will absolutely put in a contractual commitment what specific panel is being installed on your home. To be fair, most ethical companies may have to upgrade your panel to a comparable panel because of availability, as some premium panels (like Panasonic and Sunpower) have limited supplies. Don’t be afraid to ask for a contract addendum or a rider that states EXACTLY what make and model of panel you are getting.  The most efficient solar panels (as determined by independent, nonprofit member organizations that work side by side with consumers for truth, transparency, and fairness in the marketplace) are Sunpower, Panasonic, LG, Hanwha Q Cells, and Solaria.

Temperature Coefficient

Solar Watchdog, in its Industry Secrets, goes into detail about the formula about how to calculate lost efficiency, because of roof top heat, on a solar panel. The long and the short of it is that a consumer wants the solar panel temperature coefficient to be as close to 0.0 as it can get. In other words, a panel with a -0.4 has a worse temperature coefficient than a panel with a -0.3. Read the manufacturer’s data sheet to determine the temperature coefficient at Standard Test Conditions temperature (25 degrees Celsius). A panel with temperature coefficient of -0.3 will see its maximum power fall by -0.3% for every one degree hotter than 25 degrees C; for every degree below 25 degrees C, it will increase by 0.3%. Basically, seasonal temperature variations will balance out; however, temperature coefficient is a big deal in states like Texas where we only have two seasons: hot and not so hot. The manufacturers with the lowest temperature coefficients are Stion, Silevo, Panasonic, Sunpower, and LG.


Okay, so, the deal is that there are lots of salespeople out there who will flat out mislead consumers about the warranty on their systems. Each solar panel has two (2) separate warranties: (A) a performance warranty; and, (B) a product warranty. A 25-year performance warranty is run-of-the-mill. You want a 25-year PRODUCT warranty.

Performance Warranty

Performance warranties, or power output warranties, usually are around 25 years. A performance warranty covers your system if production falls below a predetermined percentage of the panels’ rated capacity. Wait. What does that mean? When a salesperson tells you that you have a 25-year warranty, what he/she usually means is that the solar panel will produce X amount of power as a percentage of peak minimum for 25 years. For example, it is not uncommon for a panel to produce north of 80% of the power it was producing on Day One for 25 years. That doesn’t mean the companies stand behind their panels for 25 years. They don’t. They don’t, UNLESS…

Product Warranty

… the manufacturer offers a 25-year product warranty. This is THE warranty that matters because this is the warranty that covers (under certain conditions and with some limitations) parts, types of damage, and/or time periods. Solar Watchdog recommends consumers upgrade to premium systems with either 20 or 25-year warranties because a product warranty includes the frame that provides structural rigidity to the panel; the glass that protects the top; the binding agent that holds parts of the panel together; the cells converting sunlight to electricity; and, the box and connectors that transfer energy.

Look, in the United States, we know that if you buy a car with a 100,000 mile warranty that car WILL start breaking down once it hits 105,000 miles on the odometer. Solar panel manufacturers know the same thing about the panels they sell. If solar is a long-term investment, why in the world would you buy something that is going to break when the system has finally paid for itself?  A 12-year product warranty means that solar panel will stop working in 12 ½ years. Be a smart consumer. Ask for panel with a 25-year product warranty. Solar Watchdog’s research reveals that there are only four companies that offer a 25-year product warranty:  LG, Panasonic, Sunpower, Silfab, and Solaria. Not surprisingly, at the time of this publication, Solar Watchdog recommends panels from all of those companies.

Solar Watchdog is aware of some companies pushing the relative newcomer Peimar Group’s solar panel. Regarding the Peimar panel warranty, Solar Watchdog states that it has one of the most disingenuous warranties on the market. In the event a consumer makes a warranty claim, according to Section 7 (b) of the Peimar Original Limited Warranty for PV Modules, THE CONSUMER has to pay for a Peimar-approved expert to make a final and binding determination about the merits of the consumer’s warranty claim. In other words, the consumer is probably going to spend more money in making the claim than just replacing the panel itself. That isn’t a warranty at all. Solar Watchdog contends that companies push panels like Peimar or Mission not because they are what is in the best interest of the consumer. Rather, companies push Peimar and Mission because they can buy those panels inexpensively on the market. In other words, they are relatively cheap panels.

The Tier One Myth

Candidly, Tier One panel designation is a good thing — a good place to start; but, it is not all that. Here is why.

Tier One panels possess four (4) qualities: (1) vertically integrated manufacturing; (2) heavy research and development; (3) advanced robotic processes; and (4) a manufacturing history of 5+ years. Now, the first three (3) combined factors afford, in theory, manufacturers more control over their products, resulting in higher quality products; however, rankings by these factors are inherently arbitrary because they are based on human judgment with no publication by Bloomberg Finance — the company that publishes the Tier One designation — of the methodology because of proprietary reasons. That means the statistics that are correlated to determine the utility of the metric of rankings are largely a secret because Bloomberg Finance does not share the metric with consumers. In other words, we can, sort of, guess at the ingredients, but we don’t know the recipe.


Solar Watchdog can state with impunity that “vertically integrated manufacturing” DOES NOT MEAN ZERO OUTSOURCING of panel production to lower tier panel manufacturers – manufacturers that have factories with inferior manual assembly lines and much less stringent quality control. Tier One panels are often assembled by a manufacturer that wears the badge of doing everything in-house (vertical integration) when that is simply not true.

With regards to “heavy” research and development, there is no objective definition of “heavy”. What is heavy to me might not be heavy to you at all. It is the same with heavy research and development. The range of what constitutes “heavy” is too broad to be considered anything other than subjective. Again, because the analysis is largely binary (heavy or not), and the metrics are unknown, it is difficult to take this pat-on-the-back by Bloomberg Finance very seriously.

With regards to advanced robotic processes, these processes often come at the expense of component quality. That means those fancy robot arms are putting in place lower quality components on those solar panels. Putting a silk hat on a pig doesn’t mean that animal is no longer a dirty pig. Garbage in and garbage out. A solar panel is like a chain — a weak link (for example, lower quality wiring and connectors) will render a weak solar panel.

With regards to the fourth factor, manufacturing history evidences the ability to address warranty issues, not panel quality. Presumably, this factor has gained ground as being important because just a few short years ago, TWO of the top 5 recommended panels filed for creditor protection under federal bankruptcy laws in the same year.

Solar Watchdog doesn’t mean to disparage completely the Tier One panel designation. We just suggest that it isn’t all what it is cracked up to be.

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