There are many module manufacturers and products on the market today, and it can be a challenge to find the best products with the right warranty coverage for a specific project from a financially stable manufacturer. For solar panels (known as “modules” in the industry) this typically is defined as a “Tier-1” or “bankable” module.

Some financial consultants, such as Bloomberg, publish their own listings of Tier-1 modules. The manufacturers have to pay to submit their qualifications, and users have to pay to buy the ratings list. The criteria to be a Tier-1 module, according to Bloomberg, is to document at least 6 projects that were financed by a bank in the last 2 years, with each one being at least 1.5 MW in size. That is a very low bar for sure, and probably hundreds of module manufacturers would qualify as “Tier-1” if they submitted their data for publication.

We encourage a more careful approach to module selection. Questions we ask involve an assessment of the strength of the company itself (its financial condition and operating history), and then look at the products specifically. For instance, does the manufacturer have any legal actions or product recalls on record. Then, how long has the manufacturer been in business and did they enter the solar module business through deliberate growth, or part of a merger or acquisition.

Out of the possible hundreds of “bankable” module manufacturers, typically a few dozen clear our stricter hurdles. Below are the criteria and questions we ask before deciding to buy a solar module.

We then use this analysis to calculate the effective cost of energy, in kWh, for the system. This energy unit measure is much more important than the typical $/Watt power metric. The power unit metric really is irrelevant, although the market focuses on it. Just like the misguided habit of focusing on Bloomberg to define what is a “Tier-1” module.




It takes a lot of effort and engineering to vet a manufacturer and a product – but we do that so our clients get the level of quality and reliability and durability that they want.

Buying a second-tier module can save 3-5% of the project’s first cost. But making that small investment in higher quality almost always delivers better performance over time: more energy, higher financial returns, less downtime, less maintenance, and a lower overall cost of energy.