Horticultural Technical Requirements

Horticultural Technical Requirements V2.1

Version 2.1Effective September 1, 2021

This page includes all information and policies related to the V2.1 Horticultural Technical Requirements, effective on September 1, 2021.


Controlled Environment Agriculture (CEA) is quickly becoming the fastest growing electric load for many utilities, with lighting representing the greatest portion of that load. Well-designed horticultural lighting products have the potential to save significant energy while optimizing plant growth and health.

The Version 2 Technical Requirements for Horticultural Lighting maintain the minimum efficacy threshold of listed products. and continue the transition from using traditional lighting metrics to using horticultural-specific metrics that better represent horticultural lighting performance. Version 2 also addresses barriers to listing multiple product variations by introducing a process for family grouping and private labeling of already listed OEM products, meaning more horticultural products will be available to choose from on the QPL.

The Version 2.1 update to the Horticultural Technical Requirements establishes eligibility and performance criteria for three new horticultural lighting product types: externally supplied actively cooled fixtures, DC-powered fixtures, and LED replacements for linear fluorescent and HID lamps. These requirements support the qualification of fixtures that enable greater whole facility energy savings by removing excess heat from the grow environment, among other strategies.

Schedule of Revisions

Version Status Effective Date Update By Delist Date Documentation
RELEASED Mar 31, 2023 -- -- Download PDF
ACTIVE Sep 1, 2021 Feb 2, 2024 Mar 31, 2024 Download PDF
ACTIVE Mar 31, 2021 Feb 2, 2024 Mar 31, 2024 Download PDF
DELISTED Oct 21, 2019 Dec 31, 2021 Jan 31, 2022 Download PDF


Unless otherwise noted, DLC policy nomenclature directly references the definitions from the American Society of Agricultural and Biological Engineers (ASABE) ANSI/ASABE S640: Quantities and Units of Electromagnetic Radiation for Plants (Photosynthetic Organisms), and, where applicable, the Illuminating Engineering Society (IES) ANSI/IES RP-16: Nomenclature and Definitions for Illuminating Engineering, with key deviations or interpretations noted. Each mention of the term “LED device” in this document is meant to reference LED packages, modules, or arrays.


Products designed and intended to operate with standard North American nominal AC line voltages (typically 120V-480V) or with DC voltages below 600V are eligible for DLC qualification. The following are further eligibility rules for horticultural lighting equipment:

  • Products that are light engines (analogous to LS-1 section or identified as retrofit kits intended to replace the light sources or other structures within an existing fixture are not eligible for qualification at this time.
  • Fixtures and/or lamps that incorporate light sources other than LED, whether as sole-source or as LED-hybrid fixtures, are not eligible for qualification at this time.
  • Products that are dynamically configurable, i.e. having no defined configuration or set of configurations and whose form factor may vary in the grow facility, are not eligible for qualification as an AC product at this time.
  • Manufacturers must list full and complete model numbers that clearly demonstrate all qualified product options offered.
    • “Full and complete model numbers” means model numbers that include all performance-affecting and non-performance-affecting variations offered, and that do not omit any option that is available to customers in the market. In general, options that do not affect the performance of the product can be submitted as a single model number, and the multiple options can be denoted by bracketing them in the model number.
    • For example, a product that has multiple exterior paint color options or mounting options that do not affect performance may include all color and mounting options in brackets (e.g. “[WH, BLK, SLV, GRY]”) within a single model number. Low and high voltage options may be submitted as a single model number (e.g. “ABC 300 [120V-277V, 347V-480V] WH”) with the worst-case performance reported. Multiple driver variations may be included in single product applications, as noted above, and listed in a single model number, as long as they perform nominally the same. If the drivers perform nominally differently – that is, they are not presented to customers as having the same performance other than voltage input and result in different ordering codes – then the unique drivers must be listed in separate model numbers. Options that affect the flux output, presence or lack of dimming capabilities, or spectral tuning options cannot be bracketed and submitted as a single model number.
    • DLC reviewers may check web listings and other marketing materials and reserve the right to request additional information to demonstrate the full and complete model number. A lack of clarity in model numbers will result in delayed application processing; misrepresentation of model numbers discovered outside the application process will generally be considered a violation of the DLC program and trademark rules and may result in delisting.
    • Each model number may only represent the fixture/lamp under a single brand. If the fixture/lamp can be sold under multiple brands, model numbers must be listed separately for each brand.

Technical Requirements

Horticultural lighting products using LEDs must comply with the provisions of this document to be eligible for listing on the DLC Solid-State Horticultural Lighting Qualified Products List.

Safety Certification

The DLC requires specific testing and reporting to ensure that all listed products have an appropriate safety certification. All products must be certified to the applicable safety standard by a safety certification organization relevant in the United States or Canada.

Family Grouping Requirements

The DLC allows family grouping applications for horticultural lighting products starting with the V2.0 Technical Requirements effective date (March 31, 2021). Family grouping applications are designed to reduce the total testing and application fees required to list groups of products that comply with the family grouping definition. Typically, parent products are based on tested data from worst-case models within a family group, and child products are based on reported data. Generally, limited testing can be provided if the worst-case models demonstrate compliance with the Technical Requirements.

Private Label Requirements

Private label applications allow manufacturers the option to list qualified products under multiple manufacturers and brands without having to conduct duplicate testing. Private label applications may only be submitted if the original equipment manufacturer’s (OEM) product is already DLC qualified. Private label products must be identical to the originally qualified versions.

Testing Lab Requirements

DLC applications require that product testing be conducted at an accredited laboratory appropriate for the performance being evaluated. These tests may include in situ measurement tests (ISTMT), LM-79, LM-80, LM-84.

Policy Clarifications and Updates

Date UpdatedChange TypeDescription Affected Document
5/6/2021ClarificationMore information on TM 33 required elementsV2.0 Policy - Pages 14-15
6/14/2021ClarificationDriver ISTMT: More information on custom and integrated drivers documentationV2.0 Policy - Page 10
6/14/2021ClarificationSpectral Tuning ISTMT: More information on spectral tuning ISTMT test report documentationV2.0 Policy - Page 13
6/14/2021Clarification General Eligibility: More information on dynamically configurable fixtures/systemsV2.0 Policy - Page 2

Testing Constraints

The DLC understands that in some scenarios, products that are required to be tested may be unable to test in the necessary apparatus’ as stated in the Horticultural Technical Requirements, due to size or other restrictions.