It’s easier than ever to buy high-quality LED lights today, but judging one against another is sometimes difficult. At the very least, a buyer should be able to know if the light is safe and efficient. Luckily, there are certifications that help a buyer know this. These are stamped on the light or the packaging. However, there is a plot twist: there is more than one certification. In fact, there are many.
It's not hard for a buyer to get lost in the flood of information. The alphabet soup of certifications—DLC, ETL, UL, ETC.—promises great quality, but if you have to weigh one standard against another, it can be confusing. Eventually you have to make a decision on which light to buy.
Let’s run through the different lighting standards and see how they compare.
DLC Rating
Many LED lights come with a DLC certification. The organization behind this standard is the DesignLights Consortium. This is a non-profit organization that issues certifications for light bulbs and fixtures. The goal of this industry-led organization is to encourage the manufacture of highly performing products that are energy efficient and high-quality.
Currently, the top DLC rating is called DLC Premium. A light with this rating is certified as having the top level of the criteria above. Not only should these lights perform well—in terms of brightness, color temperature, color rendering index (CRI), and more—but they should also have long lifespans and not suffer from long-term dimming.
UL Rating
The UL rating is a must-have mark because it indicates that a light meets strict safety standards. This rating comes from a testing laboratory called UL Solutions, formerly known as Underwriters Laboratories. The white coats at this lab test products according to their own UL standards or those set by the International Electrotechnical Commission (IEC). Not only do the standards certify safety and performance, but the rating comes with quarterly “surveillance” of the product. This surveillance lets you know that the light has a long (and safe) lifespan.
The UL 1598 standard is one of the most important LED lighting standards in the industry. It lays out requirements for performance (and how to measure it), such as lumen output and color temperature. It also sets requirements to ensure the product’s safety.
“UL-Listed” is the top rating from UL Solutions, but there is a “UL-Classified” stamp, as well. This label indicates a product has been certified as a retrofit product. In other words, a UL-Classified product (say, a light bulb) is certified to replace a bulb in a UL-Listed fixture. This allows the original fixture to maintain its UL-Listed status.
ULC Rating
It’s like the UL rating, but Canadian. This rating is issued by Underwriters Laboratories of Canada, the UL’s sister organization north of the border. The ULC rating indicates that a product meets the regulations of the Standards Council of Canada. The ULC organization, in fact, has helped create and maintain hundreds of Canadian safety standards.
ETL Rating
Yet another well regarded rating regime is the ETL, formerly known as Electrical Testing Laboratories. The ETL is an independent laboratory that uses the UL rating in its testing of products. An ETL-Listed badge is a top certification for LED lights.
The ETL-Listed rating has quite the pedigree: it originated in the work of Thomas Edison. His Lamp Testing Bureau was an early laboratory for testing the safety and quality of early light bulbs—obviously the earliest light bulbs. The laboratory eventually became the Electrical Testing Laboratories. Today, this lab is part of the Intertek Company.
Intertek tests products and rates them to many different standards: UL, ULC, ASME, ASTM, ANSI, CSA, NFPA, NOM, NSF. The testing that Intertek does is similar—sometimes identical—to that called for by most of those standards.
What is an NRTL?
An NRTL is a Nationally Recognized Testing Laboratory. This is an independent, third-party laboratory officially recognized by the Occupational Safety and Health Administration (OSHA) as having the ability to perform rigorous testing of products. In short, OSHA certifies who can certify things.
Intertek (ETL) is an NRTL. As is Underwriters Laboratories. But DLC is not an NRTL—it is an organization that uses third-party testing to certify lights (specifically lights, and under their own DLC badge) as efficient and high quality. (ETL and UL test and certify many different kinds of products, not just lights.)
What are regional standards?
Another family of standards is created by political entities (states, cities, etc.). These are actually statutory regulations that manufacturers must meet in order to be used in those jurisdictions. But if a product is labeled as “NYC Code Compliant” or “California Energy Commission” compliant, then that stamp carries the weight of a standard.
What does a testing laboratory actually do?
Every rating system is a little bit different, but there are many similarities between what laboratories do. Most laboratories follow a similar list of steps to inspect and test a product. In the case of testing an LED light, a laboratory would go through at least the following steps:
- Random sample of products: The lab grabs random samples from the manufacturer at an unannounced time.
- Visible inspection: The lab scrutinizes the light for any visible flaws.
- Electrical testing: The lab runs the light through a set of standard electrical tests.
- Mechanical testing: The lab shakes, drops, and generally abuses the light to test it for physical endurance.
- Environmental testing: The lab exposes the light to various conditions—heat, moisture, etc.—to test its ability to withstand environmental stresses.
- Performance testing: The lab measures the light’s output to properly quantify it. This includes lumen output, CRI, color temperature, and more.
- Label confirmation: The lab then uses its data to confirm whether or not the labeling is correct on the light.
If a lab issues its own listing, which is what ETL and UL do, it will certify the light as meeting all of the high standards it was tested against. If the lab does not issues its own listings, then it will pass along the data to whomever commissioned the product testing.