Solid State Lighting FAQs

Solid-State Lighting FAQs

The FAQs below represent answers to common questions about submitting a product to the DLC Solid-State Lighting QPL and how our requirements and policies are interpreted. They are explanatory only and should be viewed as such. In all cases, please refer to the Terms of Use for the operative rules regarding participating in the DLC QPL.

DLC Background

The DLC qualifies commercial LED luminaires, retrofit kits, and linear replacement lamps for inclusion in DLC members' energy efficiency rebate and incentive programs. Available product categories are prioritized and developed by DLC energy efficiency program members. The list of available categories can be found by viewing the Technical Requirements Table. Products that do not meet the intent of these categories will not be evaluated. Note that products submitted for qualification must be marketed as and intended for one of the available product categories to be eligible.

DLC publishes manufacturer and model identifying information, as well as verified tested performance or rated performance information for each product. These fields include:

  • Manufacturer
  • Brand
  • Model Number
  • Luminaire Efficacy
  • Light Output
  • Power Factor
  • Correlated Color Temperature
  • CRI
  • Wattage
  • Dimming Information
  • Light Distributions (i.e., zonal lumen density, NEMA classification, and/or spacing criteria)

The searchable Qualified Products List database is available at The QPL is intended for the use of the DLC Members in operation of their commercial lighting programs. The QPL is updated regularly as products are qualified.

The DLC team will first notify you that the application has been received via email. A DLC reviewer will review your application(s). It takes about two weeks to complete the review of your application from the time payment of the application fee is confirmed.

Upon completion of the initial review, a DLC reviewer will contact you to let you know if your product passes, fails, or requires additional clarification or application materials to determine qualification.

  • If additional application materials are required, you must provide the DLC reviewer with an estimate of when the additional information will be available and abide by the timeline established. Review of the application will commence when the additional materials are received and the application is considered complete.
  • If all documentation is provided and the product meets the Technical Requirements, the DLC reviewer will let you know that the product qualifies and the product will be listed on the QPL. If all documentation provided demonstrates the product does not meet the Technical Requirements, the product fails. The DLC reviewer will provide detailed information regarding which metrics did not meet the Technical Requirements. Any design changes made to the product after the initial review will require a new application and application fee.

The fee is $500 per Single Product Application to cover the technical review and administrative costs. The Single Product Application fee covers additional family members if the variations of those family members are limited to higher CCT, dimming variations, or variations that do not affect the performance of the product (mounting, housing color, etc). Family Grouping Application fees are dependent on the group of products submitted for qualification. Please see the Application Fees page for more details. A DLC reviewer will review the product family, determine the application fee, and confirm payment details with the manufacturer.

Credit card payments are preferred, though if that is not possible, you may pay by check. Follow the instructions on the Invoices page once logged into your manufacturer account if submitting a check. Please note that if you pay by check the DLC reviewer cannot process the application until your application is complete and payment is received.

The "Technical Requirements Version Number" field indicates the version of the Technical Requirements Table to which a listed product was evaluated when qualified. The Technical Requirements Version Number does not indicate whether or not a product meets a the most recent set of requirements, nor does it indicate if a product will be delisted during a specification transition process. Whether or not a product is delisted during the specification transition process is dependent on the performance data associated with the listing, as it compares to the current Technical Requirements, not the Technical Requirements Version Number. For example, if a product is initially listed with a previous Version Number of the Technical Requirements Table on the QPL, but meets all the Technical Requirements of next Version Number, the product will not be delisted at the end of the grace period established during the announcement of the new version of Technical Requirements. Similarly, if a product was initially listed with a previous Version Number and remains listed when a new Version Number is released, that indicates that the product is considered listed under the new version.

The DLC does not endorse any laboratory meeting the DLC Testing Laboratory Requirements. Laboratories representing the ability to qualify products and laboratory test reports indicating product performance meets DLC Technical Requirements do not represent official DLC product qualification. All decisions regarding product qualification are made by the DLC. DLC reviewers reserve the right to request documentation to clarify testing conditions or to confirm testing has been conducted by a laboratory that meets these requirements at the time of testing.

If your product is published on the QPL, you may market the product as DesignLights Consortium® qualified. Please refer to the DLC’s Logo Guidelines for instructions on proper marketing of a DLC qualified product.

Each DLC Member has access to the QPL and makes its decision about what products to incentivize based on its own program parameters, including cost-effectiveness tests. Manufacturers should work with utilities/energy efficiency program sponsors on a project-by-project basis to have their products be eligible for rebates. Please note that listing on the QPL is not a guarantee that the products will be eligible for incentives from DLC Members. Any incentives or other rebates are entirely at the discretion of the particular energy efficiency program sponsor.

The fee for a Private Label Application is based on the application fee for the originally-qualified product. The fee for private labeling for Single Product Applications is $250; this fee includes the family members listed in the Single Product Application. The fee for Family Grouping Applications is $250 for each independent test report reviewed and $25 for each additional family member of the group. For more about private labeling, please refer to the Private Label Application page.


No. Only UL Type B products, which require removal of the existing ballast from the circuit and the lamp holder to be wired with line voltage, and UL Type C products, which require the existing HID ballast to be replaced with an external LED driver, are eligible. Products that can operate using the existing HID ballast in any capacity are not eligible at this time. 

No. Only products which are specifically manufactured with an E39 base are eligible. Products with other base types that are sold with an E39 adapter are not eligible. Additionally, products with E39 bases sold with an adapter to other base types are not eligible.

Yes. Products that incorporate EX39 bases are eligible under the mogul screw-base replacements for HID lamps Primary Uses.

If a manufacturer wishes to update a qualifying product at a new voltage operating range (for example, to 120-277V, on a universal driver), the manufacturer will need to provide the additional data to demonstrate that the worst-case conditions in regard to efficacy and power quality pass the requirements (i.e., submitting another LM-79 at 120V if it was previously submitted with only an LM-79 at 277V). Because of the review needed to evaluate the additional test reports, the manufacturer must submit an additional application fee. The manufacturer should contact its DLC reviewer before submitting the payment to avoid creating an entirely new application.

No. At this time, Screw-Base Replacements for HID Lamps which incorporate functionality to allow a given model to produce multiple beam spreads/optical designs/distributions at or after the point of installation, are not currently eligible.

In reference to this particular primary use designation, the DLC is agnostic to how the product is marketed, as long as the minimum requirements are met, including base type.

The eligibility of UL types varies across lamp types and categories as outlined in the latest technical requirements. Lamps which are marketed to operate utilizing magnetic ballasts are not eligible regardless of lamp category and type, and regardless of UL operation type.
UL Type B and C products marketed to replace T12 lamps (either solely or as a lamp intended to replace either a T8 or a T12) – are eligible in the 4-foot and 8-foot general applications. UL Type A lamps marketed to replace T12 are not eligible regardless of length or general application (including 4-foot and 8-foot). Lamps claiming to replace T12s in any other general application (2-foot, 3-foot, U-bend) are not eligible. Lamps marketed to replace any other designation of fluorescent lamp are not eligible.

The 4-foot representative fixture must be a genuine product marketed and produced by the same manufacturer and have a distinct model number. The LED board of your 4-foot fixture should have no variance in the quantity, layout, or spacing of LEDs as half of your 8-foot fixture. The two lamps must also have the same type and quantity of driver(s) operating at the same drive current, and must also be of identical construction having identical cross-sections, the same tube material and thickness, and same heatsink material and extrusion.

One-lamp Type C TLEDs and one-lamp Type C 2G11-base lamps are eligible for qualification in all general applications within the Linear Replacement Lamp and Four Pin-Base Replacement Lamps for CFLs categories, respectively. This includes T8 2-foot, 3-foot, 4-foot, and 8-foot replacement lamps, T5 and T5HO 4-foot replacement lamps, U-bend replacement lamps, and Type C 2G11 base lamps.

In addition to the lamp-level testing as specified, lamps must be tested in a reference luminaire. Applicants must test 1-lamp systems in one of the configurations listed in the relevant section of the policy. Specifically:

  • Two-foot T8 replacement lamps must test with 2, 3, or 4 lamps installed in the reference luminaire
  • Three-foot T8 replacement lamps must test with 2 or 3 lamps installed in the reference luminaire
  • Four-foot T8 replacement lamps must test with 2, 3, or 4 lamps installed in the reference luminaire
  • Four-foot T5 replacement lamps must test with 2, 3, or 4 lamps installed in the reference luminaire
  • Four-foot T5HO replacement lamps must test with 3, 4, or 6 lamps installed in the reference luminaire
  • Eight-foot T8 replacement lamps must test with 2 lamps installed in the reference luminaire
  • U-bend T8 replacement lamps must test with 2 or 3 lamps installed in the reference luminaire
  • 2G11-base replacement lamps for CFLs must test with 2 or 3 lamps installed in the reference luminaire

Products should apply under, and will be listed on the QPL under, the primary use designation corresponding with the configuration of lamps used in reference luminaire testing. Single-lamp systems will note that they are single-lamp Type C systems under the “Notes” field in their listing information.

Yes. Eligible field-adjustable products must have lumen output adjustments that can be set for the project only by the manufacturer, distributor, installer, or commissioning agent before or during installation or commissioning and be performed with a control that have been made discrete to that purpose via a proprietary process or separate control. Read more about eligible field-adjustable products.

White-Tunable products producing white light, defined as chromaticity coordinates within the twenty, 7-step quadrangles of ANSI C78.377-2017 Basic and Extended Specifications became eligible with the release of SSL Technical Requirements V4.3. Products supplying colored light (i.e. points with Duv magnitudes beyond the limits of the ANSI standard and Extended specification, also known as Full Color-Tunable) are outside the scope of these proposed requirements and ineligible for listing at this time. Read more about eligibility of color-tunable products.

The DLC evaluates reported performance claims based on the information manufacturers choose to report in their product specification sheets and/or other marketing materials. If the performance claims reported in specification sheets and/or other marketing material are below the Technical Requirements, the DLC reviewer will reject the application as marketing material cannot indicate that the product’s marketed performance is below any of the Technical Requirements. To avoid delays in review, please review all marketing material prior to submitting an application to ensure it accurately reflects the product submitted, and does not contain outdated or incorrect information, or typographical errors. Please note that in addition to evaluating reported performance claims in specification sheets, the DLC will also conduct a technical review of a product’s performance via the required test data detailed in the Single Product and Family Grouping application instructions.

Yes. Both G24q-1, G24q-2, and G24q-3 and GX24q-1, GX24q-2, and GX24q-3 base types are eligible under either the Vertically- or Horizontally Mounted Four Pin-Base Replacement Lamps for CFLs General Applications.

Yes, luminaires intended to provide lighting for outdoor sports fields are eligible as Architectural Flood and Spot luminaires. Products intended for illuminating sports fields may also apply under the Specialty provisions if they desire. Please review both the Architectural Flood and Spot luminaires Technical Requirements as well as the provisions for applying under Specialty designations before applying.   

The General Application, or light output bin (low-, mid-, high-, or very high-output), is determined based on the total lumen output of the luminaire. Although DLC evaluates lumen output and efficacy based on the lumen output in the 0-90° zone, total lumen output and total efficacy is listed on the QPL. Therefore, the General Application is determined based on the total lumen output to be consistent with the information published on the QPL. See requirements for Non-Cutoff and Semi-Cutoff Wall-Mounted Area Luminaires under the Technical Requirements for more details on evaluation the performance of these products.

No, Four Pin-Base Replacement Lamps for CFLs that are capable of operating off both the existing ballast (UL Type A) and line voltage (UL Type B) are not eligible. Per the Four Pin-Base Replacement Lamps for CFLs policy, only "Plug and Play" (UL Type A) replacement lamps are eligible for qualification at this time.

No. Products that operate off DC voltage are not eligible at this time. Products submitted to the DLC must be able to connect directly to line voltage. The one exception to this policy is for Two-Foot and Four-Foot Linear Replacement Lamps that are designed to operate off the existing fluorescent ballast. In all other scenarios, including lamps specifically designed for DC voltage troffers, only products that are able to connect to line voltage are eligible. 

No. The linear replacement lamp categories are intended for LED replacements to standard two-foot or four-foot linear replacement lamps. Products that are intended to function as two lamps combined together are not eligible for qualification at this time. This includes products with 4 pins at each end, as well as products which appear to be two lamps welded together. Below are some examples of products that are not currently eligible under the linear replacement lamp categories.

Yes. Luminaires intended to provide illumination to the facade of billboards are eligible as Architectural Flood and Spot or Landscape/Accent Flood and Spot Luminaires. These products are NOT eligible for the Outdoor Pole/Arm-Mounted Area and Roadway Luminaires category. Remember to review the Technical Requirements Table for each category to determine if your product would meet the listed requirements before applying.

Yes, these products are eligible, so long as those LEDs are not dynamically controlled for purposes of color-tuning. As with the general multiple-LED-types policy, LM-80 and ISTMT testing must be provided that covers both LEDs. If the LEDs are covered by the same LM-80, only the hottest LED overall will need to be tested. Please note, that DLC normally expects that, if other parameters are equal, lower CCT will be hotter than higher CCTs. 

Application Requirements

No. The DLC requirements state that products within a family group of white-tunable products must have the same types of LEDs, and an identical technological approach to color output. This is intended to include a restriction that all products within a family group have the same tunable range. Therefore, as an example, if one version of a product can tune from 2700-5000K, while another version can tune from 2200-6500K, they must be submitted under separate applications, with independent testing.

If submitting a Single/Family application where the safety documentation involves a multiple listing document, please submit the private labeler compliance certificate and populate the Application Form with the safety organization and private labeler safety file number. If the safety organization has not provided a private labeler compliance certificate, one will need to be obtained from the safety organization in order to proceed with the Single/Family application process.

Yes. As of Technical Requirements V4.3, implemented on March 26, 2018, providing safety certification documentation is required for all types of Update Applications. Please refer to the Safety Certification page for more information on what safety certification documentation is required.

No. Per the Linear Replacement Lamp Requirements, lamps that require the use of specialized accessory components in order to meet the stated requirements are not eligible for qualification. The DLC reserves the right to ask for additional information regarding any components included in the testing with the product submitted, and deem a product not eligible for qualification.

Examples of specialized components that are not eligible include the use of socket extenders to shorten the distance between lamp holders and changing the lamp holders from G13-base to G5 base, or vice-versa. However, replacement of the existing fluorescent troffer sockets is allowed, and not considered a specialized component, if the replacement is specifically to change the lamp holders from shunted to unshunted, or vice versa, for safety compliance.

If the incorrect information in the LM-79 or ISTMT is first identified by the applicant, unprompted by the reviewer, the DLC will accept a revised test report. All test report revisions must follow the rules set forth by the accreditation body. If the incorrect information is first identified by the reviewer, the DLC will not accept a revised test report, and will require the product to be retested. In the event of a retest, the DLC will only reevaluate the new, retested data. Data issues encountered in LM-80 reports will be handled on a case by case basis. The DLC urges all applicants to thoroughly review all application documentation prior to submittal to ensure all information submitted is accurate.

In the event that the test report contains failing test data that is not representative of the products performance, please see the FAQ, “I believe that the test report I submitted with my application does not represent my product's performance. Will the DLC accept a new report with different performance on the same product design?”

No. In the event that the test report submitted does not meet the Technical Requirements, the DLC will not accept a revised test report unless a design change has been made to the product. Please note that the Self Certification Statement provided which each application includes language that the applicant certifies all model numbers submitted meet minimum requirements. In the event where a manufacturer chooses to make a design change to the product, and resubmit test data that represents that design change, the DLC will need detailed explanations of the changes made as well as assurance that the changes will be reflected in all products sold. If choosing to make a design change, the manufacturer must create and submit a new application, and pay the associated application fees for the review of the redesigned product(s). If a test report submitted does meet the Technical Requirements, but includes incorrect information, please see FAQ, “I submitted a test report that meets the Technical Requirements, but noticed that there is incorrect information reported. Will the DLC accept a revised test report?”

When submitting an application containing White-Tunable products, the Scaled Performance Table must be populated with the performance data representative of the least efficacious setting of each product seeking qualification. For more information regarding White-Tunable applications, please refer to Testing and Reporting Requirements for Color-Tunable Products.

If you are private labeling a product, the intention is that you are using your own company’s name and model number to market an OEM product to your customers. If you are reselling a product as a Private Labeler, you may not use your name and/or model number to market and resell the product as DLC listed without first listing that name and model number on the QPL. To do so, you must submit a private label application. When private labeling, it is imperative to reference the DLC’s Private Labeling policy to ensure the products, as your company markets them, are searchable on the QPL. It is not acceptable to reference a “DLC Partner”, “DLC Manufacturer”, “DLC Model Number”, or anything similar alongside your own name and model number.
If you are simply selling DLC qualified products as a distributor under the exact name and model number explicitly listed on the QPL under the OEM information (manufacturer name, manufacturer brand, model number), you do not need to private label the product.

No. The DLC is interested in the performance of the production-ready product seeking qualification. As such, test data on prototypes will not be accepted for DLC submissions. Testing must be on production-ready models that are identical in design and construction to those that are being or will be sold.

Please see FAQ, “Can I test and include a bracketing worst-case product in a Family Grouping Application solely for submitting to DLC, even though I do not intend to sell this product variation?”, if you are submitting a production-ready product as a worst-case bracket that is not currently planned to be sold to customers. 

Yes, under specific circumstances. Configurations of multiple luminaires mounted on a singular mounting structure can be listed in one line item on the QPL, provided that each mounting configuration includes only identical luminaires, and the configuration of luminaires is identifiable in the ordering code nomenclature. This provision is only applicable for products within the Outdoor Pole/Arm-Mounted Area and Roadway Luminaires, Outdoor Pole/Arm-Mounted Decorative Luminaires, Landscape/Accent Flood and Spot Luminaires, and Architectural Flood/Spot Luminaires Primary Use Designations.

Additionally, products that wish to utilize this listing approach must be submitted via a Family Grouping application. An example of a product design that would be eligible for bracketing includes a pole-mounted area luminaire that can be ordered in configurations of 1, 2, 3, or 4 luminaires mounted to a singular pole. In this example, the 1, 2, 3, and 4 luminaire configurations can be bracketed within a singular model number. The form of the model number should be submitted as:

  • ABC-123-[1, (2, 3, 4 see notes)]

The “Notes” field on the QPL will then state:

  • “Available in configurations with multiple identical heads where model number indicates 1=1 fixture, 2 = 2 fixtures, 3 = 3 fixtures, 4 = 4 fixtures”, etc… – as needed based on specific number of configurations offered using identical fixtures.

The Outdoor Pole/Arm-Mounted Area and Roadway Luminaires and Outdoor Wall-Mounted Area Luminaires category are designed for luminaires intended to light up general areas. The Architectural Flood and Spot Luminaires category is designed for luminaires intended to light up specific items/objects/elements. The floodlight category cannot be used to qualify area lights that would not meet the zonal lumen requirements of the Outdoor Pole/Arm-Mounted Area Luminaires or Outdoor Wall-Mounted Luminaires category.

The intent of the Private Label application policy is to allow products that are exactly the same as ones already listed on the QPL to be listed. Because of this relatability, products do not need to go through redundant testing, and application fees are reduced due to a simplified application review process. However, because this process is enabled for products that are identical, the DLC lists private labeled versions of products with exactly the same performance information as their OEM versions. The reasoning behind this is that identical products should have identical performance ratings, even if brand, manufacturer, model number, date qualified, and similar descriptive fields are necessarily different.

As additional clarification, during transitions to new versions of Technical Requirements, if a previously-qualified OEM product is listed at a certain classification (i.e. as a Premium product) due to the requirements in place at the time of its qualification, and a private label is sought during a time when products are only being evaluated against a new set of requirements, the private label will only be listed with respect to how that product performs relative to the requirements in place at the time of its qualification.

For example, if an OEM product was qualified under the V3.1 requirements as meeting the Premium classification, but does not meet the V4.0 Premium requirements, then applications seeking to Private Label that product received after the 8/31 cutoff will be listed as meeting the V4.0 Standard requirements, not as V3.1 Premium (see details of the V4.0 transition and the 8/31 cutoff in the Cover Letter and Guidance that was distributed with the announcement, as well as in the explanatory webinar and Transition Guidance session from the DLC Stakeholder Meeting).

No. While the DLC does not require testing in all approved and pre-approved housings available for each retrofit kit or replacement lamp Primary Use, the approved and pre-approved housings selected for testing are intended to provide similar, common environments for which the retrofit kit may be installed in the field. As such, it is the DLC's expectation that the submitted retrofit kit should meet the requirements regardless of the housing chosen for testing. If testing is provided showing that the product does not meet the requirements in a specific housing, the products will not be able to be qualified and listed on the QPL. For additional information regarding the resubmission of test data on the same product design, please refer to the following FAQ

Yes. To ensure all products listed on the QPL are associated with at least one line item that includes tested data, Private Label applications must include at least one of the Parent models of the OEM listing. If the private labeler does not wish to include at least one of the Parent models of the original OEM listing, the private labeler must provide test data for the worst case model of the OEM products they do wish to private label, which will be assessed at the full application fee required for the evaluation of independent reports (ITRs). This product will then be listed as the parent product for the private label listing. 

DLC Members have expressed a need to be able to identify products that are able to dim with certain characteristics. The DLC now collects and reports specific dimming information to accommodate this need. For more information on how to report dimming information, please refer to the guidance document (pdf)

Yes. If a private labeler wishes to extend the private label to a third organization, there are two options. One, the private label request letter can be signed by the original manufacturer and the final private labeler. For example, if company B private labels a product from company A, and then company C wishes to private label that product from company B, the private label request letter would be signed by company A and company C.

Alternatively, the original manufacturer can provide a blanket letter that grants the first private labeler permission to private label any product they manufacture to a third organization. Requests for private labeling from the initial private labeler and the third organization would then need a letter signed only by those two parties, along with the letter from the original manufacturer. In the scenario above, this would mean company A provides a blanket letter for company B to private label their products; then applications for products from company C would need to include both that letter and the signed letter between company B and company C.

Because they have different light output and distribution requirements, center and end units for vertical refrigerated case lights may not be submitted in the same single product application. They should either be submitted as separate applications, or applied for under the family grouping policy. Family groups that include both center and end units must demonstrate compliance with the requirements on worst-case light output of both center and end units.

A Low-Bay luminaire is classified by a lumen output between 5,000 and 10,000 lumens (with established tolerances). A High-Bay luminaire is classified by a lumen output greater than or equal to 10,000 lumens (with established tolerances). Please refer to the Eligibility Requirements and Technical Requirements for additional information.

All Stairwell/Passageway Lighting must be capable of at least bi-level dimming. Graduate dimming is acceptable, as long as the controls dim the fixture to a lower-power state when the space is not occupied. Documentation of dimming and controls must be provided with the application.

All occupancy sensors for the Stairwell/Passageway Lighting category are acceptable, as long as they meet the following requirements:

  1. Luminaires that include integral controls for occupancy sensing and bi-level dimming.
  2. Luminaires that operate off remote occupancy sensors, including wireless options, where a remote sensor(s) is sold packaged together with a luminaire(s) under a single model number or ordering code.
  3. Luminaires that operate off remote occupancy sensors, including wireless options, where the luminaire and sensor are sold separately, but the luminaire has features enabling communication with a remote sensor(s).


For white-tunable product submissions, manufacturers must report the performance for their least-efficacious product within their group according to Table 1 in the requirements. Performance must be reported for one point within each ANSI quadrangle the product is able to tune to. The language in the policy is not intended to state that performance must be reported for the highest CCT and lowest CCT within each quadrangle, but rather one point in each quadrangle from the lowest CCT to the highest CCT the product can tune to.

Yes. Production-ready models that are identical in design and construction to the other product variations in the family, but differ in a measurable parameter to represent a worst case performance metric (i.e. worst case thermal member), can be included in a Family Grouping application if the corresponding test data is provided. For example, this is commonly seen in products with a higher LED drive current than what is intended to be offered to customers to represent the worst case thermal member. A description of the testing rationale is required, and may require additional details during the review.

Note that there may be additional implications if any of the products described above cannot be procured for Surveillance Testing purposes. For instance, if one of these worst-case brackets is selected for Surveillance Testing but cannot be procured by the DLC, then the product will be de-listed in accordance with the Surveillance Testing Policy. In this situation, the remaining family members would need to be re-bracketed or the entire family may be de-listed. It is up to each manufacturer to weigh the advantages and disadvantages associated with including non-procurable worst-case product brackets.

Any product with a unique optical design that results in a unique distribution requires submittal of an IES file to evaluate the zonal lumen distribution. For Single Product applications, where optical and distribution variations are not permitted, only one IES file is required. For Family Grouping applications, where optical and distribution variations are allowed, an IES file for each unique optical and distribution pattern is required. This requirement applies to any variation in the product design that would impact the overall distribution of the product, including but not limited to: TIR optics, lenses, reflectors, refractors, and products of different geometries (i.e. screw-base replacements of different lengths).

For family groups, each of the required LM-79 reports for “worst case” performance must include the necessary information for DLC to verify that the parameter in question meets the DLC requirements. For example, the “lowest light output” LM-79 test report must include light output measurements.

Manufacturers should always be considering worst-case across all product variations, including input voltage, before submitting test data to the DLC. However, in the event that the electrical testing demonstrates a higher wattage at a different voltage than the photometric testing was conducted, the DLC will allow worst-case efficacy to be calculated from taking the lumen output from the photometric testing and dividing by the higher wattage from the electrical testing. This calculation approach is permitted to reduce testing burden rather than requiring the manufacturer to retest light output at the worst-case operating voltage. This approach is only allowed when the only variable between the LM-79 lumen output test and the electrical test is input voltage, and is based on the premise that the driver output (and therefore lumen output) will not significantly change with input voltage. If using the calculation approach, the DLC reserves the right to ask additional questions to confirm the input voltage is not impacting the drive current to the LEDs before moving forward with the review. The calculated efficacy will be listed as the Measured Efficacy on the QPL. If the manufacturer chooses to retest at the worst-case operating voltage instead of conducting the calculation, the retested values will supersede any calculations. 

The DLC lists these products, when qualified, by unit with unit-level performance data for light output characteristics. The DLC understands that most refrigerator case lighting products are sold as systems with multiple units attached to a power supply. Individual units connected alone on the same power supply used in the system will not perform the same as they would when the total system is connected to the power supply because of efficiency variance based on the load on the power supply.

To obtain unit-level data that is accurate for an individual unit when installed in the system, the DLC would like testing conducted as follows:

  • Each individual unit should be tested alone using the goniophotometer method according to LM-79 for light output and light distribution measurements. From this testing, the DLC will obtain the light output and light distribution (zonal lumen density) information.
  • The worst-case system configuration should be tested (using either the integrating sphere method or goniophotometer utilizing a spectroradiometer method according to LM-79) for the other necessary metrics: efficacy, color, etc. The worst-case system will be the variation in your product line that would result in the lowest efficacy – typically at the worst (smallest) loading conditions for a given power supply – that you would sell as a new system commercially. The DLC will use this efficacy measurement to determine compliance with the DLC requirements.

The DLC will evaluate the individual unit efficacy as if it is equal to the system efficacy when the unit is installed in that system. In this way, the DLC will still be identifying unit-level data in the worst case scenario of a refrigerator case lighting system to evaluate against the unit-specific performance specifications. If the manufacturer chooses to provide another system configuration, a technical rationale of why the system exhibits the worst case efficacy must be provided. The technical rationale should be based on in-house data or other analysis.

Because refrigerator case lighting systems utilize external power supplies, manufacturers often use various power supplies or combinations of power supplies to attain the appropriate loads. Refrigerated case luminaire applications are held to the same driver variation policies detailed in the Family Grouping policy.

In all cases, testing must be provided at the worst-case performance among a product’s different operating modes, as the Technical Requirements for each category are minimum performance requirements. Due to design complexities of SSL luminaires and the many variables that could affect each performance metric with a minimum requirement, it is difficult to prescribe what worst case will be for all situations. It is the manufacturer’s responsibility to identify the worst-case operating mode of the product for each performance metric requirement and provide the appropriate test data. The DLC always reserves the right to ask for details of how worst-case was determined, including supporting engineering analysis and test data supporting the selection, as deemed necessary.

Our understanding of the technology has led us to expect certain operating modes and design choices to be the worst cases. Power factor and THD are commonly seen to be worst case at 277V, while photometrics (specifically efficacy) are commonly worst case at 120V. This is not necessarily true for all luminaire designs, so a manufacturer may submit independent test data for a different operating mode if it is accompanied by a technical rationale and supporting data (independent or in-house) demonstrating that what was tested is in fact the worst case. If testing is not conducted according to the expectations described above, DLC reviewers will ask for the testing at the expected worst case operating modes, or a technical rationale with supporting data for an alternate worst case operating mode for both electricals (power factor and THD) and photometrics.

Alternately, if the voltage inputs for a product include 347V and/or 480V options, manufacturers will be expected to provide a rationale for how worst-case was determined, or test data at all voltages if a rationale cannot be provided for a particular operating mode.

When submitting applications for products using universal drivers, be sure to test at the appropriate operating mode for both photometric and electrical measurements. Please note that the DLC requires the current THD (“THDi” or “ATHD”) performance, not voltage THD.

Power factor and THD requirements:

Metric Requirement Tolerance Actual Requirement
Power Factor ≥ 0.9 (≥ 90%) - 0.3 (- 3%) ≥ 0.87 (≥ 87%)
THD ≤ 20% + 5% ≤ 25%

If both integrating sphere and goniophotometer measurements are submitted, the DLC will evaluate the lower performing values between the two measurement methods. Both measurement methods are acceptable methods for measuring the photometric performance of a product as defined by IES LM-79-08 Approved Method: Electrical and Photometric Measurements of Solid-State Lighting Products. Additionally, the DLC requires that products meet the Technical Requirements regardless of the approved method used to measure performance. In the event that the measurements conducted by one method do not meet the requirements, the DLC will not ignore those measurements and evaluate the better performing measurements conducted by the other method. Please see FAQ “I submitted a test report that contains failing data, but believe this data does not represent my product's performance. Will DLC accept a new report with different performance on the same product design?” for more information on the DLC’s policies on submitting test reports that contain failing data.

Please refer to the guidance and links on the Testing Lab Requirements page on the DLC website.

No. To remain fair and consistent across manufacturers submitting applications to the DLC, the DLC must strictly enforce its policies and cannot make ad hoc exceptions, even if there is a sound technical justification for the alternate approach to testing. In situations where the testing does not follow DLC policy, the DLC will require the product be retested according to policy, or may decide that the product is ineligible if retesting according to policy is not a viable option.

Policy revisions occur periodically. For more information on past and present policy development efforts, please see Policy Development. The DLC is very open to suggestions for policy revisions; if you have a suggested revision to a policy, please submit the request to for consideration during policy development cycles.

Please note that clarifications to existing policies can be found via this FAQ page.

In reviewing Pre-approved Equivalent requests, the DLC is verifying that the requested incumbent fixture is/has:

  • Commonly used in the application category for which the retrofit kit is applying
  • Specifications that align with the application category for which the retrofit kit is applying
  • Similar thermal environment (i.e. internal volume and construction materials) to those listed under the Approved section of each Primary Use

If the above information is not clear in the spec sheet provided for the requested fixture, the DLC will require additional information to ensure the requested fixture aligns with the Approved fixtures of that given Primary Use. Pre-approved Equivalent requests may be sent to

Yes. Due to the system-level testing configuration acceptability (see Testing Notes under Testing & Reporting Requirements for Linear Replacement Lamps) of Type C Linear Replacement Lamps, THD and Power Factor measurements will be accepted when measured inside the appropriate reference troffer if bare-lamp electrical testing is not available. Please note that this consideration only applies to Type C Linear Replacement Lamps, where more than one lamp is powered by a dedicated driver.

Testing must be conducted at each end of the acceptable voltage range of the ballast.

Any variation that would affect electrical compatibility with the existing CFL ballast must be tested for compatibility. This means that wattage variations and dimming variations need compatibility testing, while CCT or optic (beam angle) variations do not. Feedback on the application of family grouping rules is welcome; please contact

Luminaire efficacy should be reported as the total luminous flux from the fixture divided by the total input power. Luminous flux is based on the photopic luminous efficiency function (V lambda), not scotopic or mesopic efficiency.

Efficacy, power factor, and THD are calculated based upon the complete system required to install the product. The system may include an internal driver, an external driver, and/or an instant start ballast depending on the product submitted.

It is the manufacturer’s responsibility to determine the “worst case” product of the group/sub-group. The worst-performing product can be identified through engineering analysis and/or in-house testing of all family members. If engineering analysis is used to identify worst case, the tested value associated with the worst-case product may be higher than scaled values indicating the performance of other family members. If this is the case, the manufacturer must provide an explanation that addresses the variance between scaled values and tested values, and the reviewer must understand the manufacturer’s scaling method before the application process may continue.

For any performance metrics that are measured as a percentage, corresponding tolerances refer to percentage points. For example, a power factor requirement of ≥ 0.90 (i.e. ≥ 90%) with a -3% tolerance implies a functional requirement of ≥ 0.87 (i.e. ≥ 87%). For performance metrics that are not measured as a percentage, the tolerance is a percentage of the required value. For example, for a minimum efficacy requirement of 60 lm/W with a -3% tolerance, the functional requirement is 58.2 lm/W (i.e. 60 – 3% = 58.2).

According to ENERGY STAR Manufacturer’s Guide for Qualifying Solid State Lighting Luminaires – Version 2.1, the measured temperature from an ISTMT has a tolerance of ≤ 1.1°C or 0.4%, whichever is greater due to thermocouple tolerance. This may change the appropriate In-Situ case temperature (Tc,°C) to enter into the ENERGY STAR TM-21 calculator. For example, a measured In-Situ case temperature of 86.1°C may be entered as 85°C to comply with an 85°C case temperature data set from the LM-80 report.

The DLC will accept a 5% tolerance on the drive current used in the LM-80 report to verify lumen maintenance compliance through Option 1. The LED drive current of the submitted product may be 5% greater than the drive current used during LM-80 testing. For example, an LM-80 report at 700mA may be used to qualify a luminaire with an LED drive current ≤ 735mA.