Selecting solar panels: how to compare quality of solar equipment
Last updated 6/25/2019
All solar equipment–from solar panels to inverters to batteries–has a long list of specifications to help you understand its performance, quality, and durability. But individual technical specifications and warranties don’t provide you with a complete picture of how one panel, inverter or battery compares to another, making it hard to select the best solar equipment for your unique needs.
In collaboration with the National Renewable Energy Laboratory (NREL), EnergySage developed a straightforward, industry-standard system for classifying and comparing the best solar panels, inverters and batteries by evaluating key criteria.
The rating system categorizes all solar equipment on a five-tier scale, from Poor to Fair, through Good and Very Good, and ultimately up to Excellent. The classifications are displayed on each panel, inverter and battery page in the EnergySage Buyer’s Guide, and are provided alongside every quote that is submitted through the EnergySage Solar Marketplace to help shoppers compare their options and choose the best solar panels for their needs.
Solar equipment types: how the EnergySage rating system works
There are dozens of solar panel, inverter and energy storage manufacturers on the market in the U.S., and each offers many models of products. Even the most research-oriented consumer would be overwhelmed by the task of reviewing, aggregating and comparing the technical specifications for each of these products. However, at EnergySage, we believe that choosing the best solar panel for your solar energy system does not have to be a harrowing or time-consuming experience.
Our objective, fact-based classification system was developed in order to help quickly inform your solar purchasing decision. We compiled and evaluated technical specification sheets, support agreements, warranties, and other publicly available documents, and used that information to assign a rating to all solar equipment available in the U.S. market.
Solar equipment classification
The EnergySage classification system incorporates technical specifications for solar panels, inverters and batteries to compare their performance, durability, warranty and overall quality. By assessing each product across a range of metrics, the EnergySage rating system groups equipment into five different classifications: Poor, Fair, Good, Very Good and Excellent.
Solar equipment–whether panels, inverters or batteries–rated as Poor or Fair are at the low end of what is currently available in the market, or may be outdated models no longer produced by manufacturers and rarely stocked by solar installation companies. Equipment receiving Good, Very Good or Excellent ratings must meet a baseline set of criteria rigorously developed so that you can be confident that your solar energy system will meet your needs.
How to choose the best solar equipment for your needs
EnergySage has classified all types of solar equipment into an easy-to-understand framework:
Excellent solar equipment
Equipment earning the Excellent rating is ideal for maximizing the performance of your solar energy system. The criteria vary for each type of solar equipment and represents the best available technology in the U.S. market. You’ll likely pay a higher upfront price for the exceptional performance, quality, durability, and warranty coverage of Excellent solar equipment.
- Panels: produce more electricity over a smaller area and last longer than other panels, though they may come at a price premium.
- Inverters: very efficient at converting DC to AC electricity, operate across a wide range of voltages, and have above average warranties.
- Batteries: very efficient at storing larger amounts of electricity, and maintain that high performance for many years.
Very Good solar equipment
Equipment earning the Very Good rating performs above average across a range of criteria, and may only miss out on the highest ranking due to a shorter warranty, lower efficiency, or decreased performance under sub-standard conditions. You can expect strong performance and slightly lower costs than associated with Excellent equipment.
Good solar equipment
Equipment earning a Good rating is a safe and solid choice for your solar energy system under most circumstances. This equipment is in the average range for most or all technical criteria analyzed, though may offer a shorter-than-average warranty. Good solar equipment is ideal for solar shoppers seeking a bargain for their solar energy system.
Fair solar equipment
Equipment receiving a Fair rating is at the low end of what is available for solar equipment today. This equipment may be older, no longer produced by manufacturers and likely rarely stocked by solar installation companies. Fair solar equipment may have received a higher rating during previous iterations of this rating system, but now has dropped in quality as the technology available across the rest of the industry has improved.
Poor solar equipment
Solar equipment receiving a Poor rating is at the bottom end of the spectrum of solar equipment, and should be priced accordingly if at all available. This equipment has been surpassed by advances in technology and performance of other equipment available in the industry.
Unrated solar equipment
Solar equipment is listed as Unrated if its technical specifications sheet does not include information necessary for the rating system.