By Austin A. Gelder / Lighting Performance Technical Advisor


In June, DesignLights™ Consortium (DLC) announced the final version of its Technical Requirements Table V4.0, which significantly increases the efficacy requirements for products to remain DLC qualified. Shortly thereafter, several additional proposals were introduced and have the potential to expand the DLC program to additional product types.

Technical Requirements Table V4.0:

The primary changes from the V3.0 to V4.0 requirements are the increases in efficacy, although there are also minor changes that will allow the DLC some flexibility to address specific situations in the future.

Unlike the 2015 V3.0 updates, which reorganized the specification, V4.0 updates are relatively straightforward as they raise the efficacy bar for every category. The DLC’s reasoning for this is that the requirements had not been meaningfully increased since 2014 but the efficacy of products has been steadily increasing.


The increases in luminaire efficacy are significant, with DLC Standard Efficacy products increasing 20 to 30 lumens per watt and DLC Premium Efficacy products increasing 10 to 40 lumens per watt. A full comparison of existing V3.X to new V4.0 requirements is below:


Similar to the increase in efficacy for luminaires, there has been an increase in the efficacy requirements for Lamps. The efficacy increases for E39 type lamps are the most significant, rising 15 to 25 lumens per watt.

Allowances and Other Changes:

In addition to the changes in efficacy, the technical requirements also include a new section that refers to allowances for lower efficacy for specific product type and feature combinations. This section is currently empty as there are no specific allowances included yet, but this allows DLC some flexibility in the future based on feedback and suggestions that they receive. This is, in a way, similar to the specialty luminaires in that the DLC is keeping the door open for situations that were not anticipated in their specification development process.

The other minor change included in the V4.0 technical requirements is the ability to report TM-30 data. This is not a requirement, but is notable for the partial adoption of such a recent metric. This change allows those who target a high TM-30 score the ability to distinguish their product while also offering additional decision tools to those looking for more information on color quality.

DLC Proposals for V4.1 (and Beyond):

DLC has several proposals that would expand the reach of the DLC program to include additional products. It is important to note that these are not effective yet, but are a good indication of how DLC intends to change its program in the future.

Outdoor Very High Output:

Part of the proposed V4.1 would separate out the “Outdoor High Output” category of luminaires, which currently includes everything over 10,000 lumens, and split it into two categories. The categories would be the existing High Output category, which would include products from 10,000 to 24,999 lumens, and a Very High Output category for products that produce 25,000 or more lumens. This change aims to address the large number of products that far exceed the minimum output to be considered an “Outdoor High Output” luminaire while also capturing some of the additional energy savings that can be found by increasing the efficacy on these “Outdoor Very High Output” products.

U-Bend SSL Lamps:

While DLC has covered linear SSL replacements for tube-style lamps for some time, they have not included the U-bend versions of these lamps. The V4.1 proposal to add the U-bend is a welcome one, particularly for those who experience the high shipping costs and breakage rates associated with legacy fluorescent products. No specifics have been given, but the requirements are likely to mirror those of the 4-foot T8 lamp replacements and would likely include measurement in a luminaire.

T5 SSL Replacement Lamps:

While mentioned in the V4.1 proposal as an area of interest to DLC members, there is not a proposal to include these products; however, DLC may consider including these products in future revisions, and they would likely assign requirements that differ from those covering T8 lamps.

Hazardous Location Luminaires:

In response to a large number of products applying for the special category for Hazardous Location Luminaires, DLC indicated in the V4.1 proposal that they intend to develop requirements for defining what a product must be considered to be a hazardous location luminaire. This is an early indication, but could include IP ratings, safety ratings and classifications per the National Electrical Code or Canadian Electrical Code.

Refrigerator Case Lighting Revision:

In the V4.1 proposal, DLC revised the definition of refrigerator case lighting to only allow pin-type connections that support electrical connections for refrigerator case lighting products. Products using pins for mechanical support will not be permitted. Products that use the pins for mechanical and electrical support would be better categorized as tubular LED lamps. This revision would provide a potential loophole and would impact already certified products.

Additional Proposals:

In addition to the V4.1 proposal, DLC issued a number of other proposals that would include expansions and additional requirements.

Safety Certification:

While DLC has required proof of safety certification since V3.0, they issued a proposal to require proof of safety certification for private labelers. Many partners not having safety certification multiple listed in their own name causes additional work and concern regarding the program and this proposal is intended to eliminate those concerns.

Wider CCT Range:

DLC proposed adopting the newer ANSI C78.377-2015 standard for CCT and chromaticity, which has the biggest impact of allowing for very low CCT products in the 2200K and 2500K CCT ranges. It would not extend the high end limit of 5000K or 5700K (as applicable to the product); however, lower CCTs would allow for indoor products to give the appearance of dimmed incandescent or for outdoor products to have a lower CCT to address desires to replicate an incandescent or gas lamp type appearance.

DC Powered Products:

One of the more significant DLC proposals addresses the potential qualification of DC powered products. This will allow for some of the unique systems that enable connection to microgrids (including those that tie into renewable energy, such as solar and/or wind energy). This also includes Power Over Ethernet (POE) products, which allow for easy repositioning of Luminaires within a space due to the low voltage that is provided to the luminaires.

DLC must answer many questions before including DC powered products, but most of these questions focus on how to consider this type of energy efficiency. DC systems also have additional considerations, such as the external AC to DC conversion from the grid, and, depending on voltage, wiring can have a major impact on the efficiency of the system.

4-Pin SSL Replacement Lamps for CFLs:

Another significant expansion proposal is to include SSL replacements for 4-pin compact fluorescent lamps. These products are common in many commercial applications but are not currently covered by any energy efficiency program. The current proposal would include some similarities to measuring linear fluorescent lamps, such as performance in a luminaire. DLC is also including some pre-approved equivalent luminaires and pre-approved equivalent ballasts.

Alternates to these lists are allowed but are considered by the DLC on a case by case basis. It was noted that the DLC would be updating lists, so additional approved fixtures for these products would be included over time. The general categories of fixture are horizontally mounted downlights and vertically mounted downlights. The products can test in any category fixture and, given the allowable categories, are likely to focus on one application or the other, as CFL downlights are not the most efficient at redistributing light due to the large size of the source.


The biggest change in the near future involves required efficacy levels, which will impact many of the currently certified products. Existing products that meet the requirements will continue on to V4.0 without change, but it is also a good time to update product performance if changes have been made to LEDs or drivers. DLC Premium products will be downgraded to standard if they do not meet the new premium requirements, but will otherwise carry over.

Many proposals were made, but they remain just that: proposals. Which of the proposals will be adopted, and what modifications to the proposals are enacted, will be important to watch. The future holds additional opportunities for products that have not been able to achieve DLC qualification in the past and will open up the opportunity for incentives to a wider range of projects.