Frequently Asked Questions about the CALiPER Program
This page addresses many of the questions manufacturers, testing laboratories, consumers, retailers, and energy efficiency program sponsors may have about the DOE SSL Commercially Available LED Product Evaluation and Reporting (CALiPER) program.
- What is CALiPER?
- How are products selected for CALiPER testing?
- Can I submit my product for CALiPER testing?
- Can I submit my previously tested product for a retest?
- What is the CALiPER Program No Commercial Use Policy?
- Why does CALiPER test the entire luminaire rather than the LED device itself?
- Do the CALiPER tests take into consideration the luminaire junction temperature, ensuring that the tested product will maintain its expected life?
- Does CALiPER do benchmark testing?
- What role does CALiPER play in the SSL standards process?
- Are CALiPER tests verifiable and repeatable?
- Can specifications for a lighting project require that submitted fixtures be CALiPER tested?
DOE's SSL Commercially Available LED Product Evaluation and Reporting (CALiPER) program independently tests and provides unbiased information on the performance of commercially available SSL products. The test results guide DOE planning for R&D and market development activities, provide objective product performance information to the public, and inform the development and refinement of standards and test procedures for SSL products.
DOE supports testing of a wide, representative array of SSL products available for general illumination, using industry-approved test procedures. Guidelines for product selection ensure that the overall set of tests provides insight on a range of lighting applications and product categories, a range of performance characteristics, a mix of manufacturers, a variety of LED devices, and variations in geometric configurations that may affect testing and performance.
Commercially available products are purchased and then tested by one of several accredited lighting testing laboratories arranged to assist this program. All luminaires are tested with both spectroradiometry (in an integrating sphere) and goniophotometry, along with temperature measurements (taken at the hottest accessible spots on the luminaire) and off-state power consumption.
Manufacturers of tested products are given an opportunity to comment on test results prior to their finalization. Testing results, summaries, and interpretations are distributed in hard copy and via the DOE SSL website. Requested detailed testing results are sent via email. (See the CALiPER No Commercial Use Policy.)
To be eligible for CALiPER testing, products must be available for purchase on the open market. Products are selected to cover a full range of commercially available products for the general illumination market. The wide range of tested products aims to enable buyers and specifiers to make more informed choices about SSL products and provide useful information for DOE's SSL R&D program.
CALiPER products are selected using a number of criteria, including performance claims, product visibility, market impact, and specific design characteristics. Selection may also take into account availability, cost, and need; CALiPER often tests similar lamp types together (downlights, undercabinet lights, outdoor lighting, etc.) in order to compare performance with one another as well as with traditional lighting technologies. CALiPER also chooses products from a wide range of manufacturers and lighting types to ensure fairness, balance, and program credibility.
Submissions or requests for inclusion in the testing program cannot be accepted. All products tested are purchased on the open market through normal channels (retail, distribution, or online sales). However, if your product is marketed (via your website or distributor websites or in industry publications), then it will be entered in our product tracking program and might be selected for testing in a subsequent round of testing. The selection process relies on a number of criteria, such as luminaire design, expected performance, and expected market impact.
Manufacturers may request retesting of a product that has previously been tested by the CALiPER program under the condition that the manufacturer pays for the test (at a minimum, an integrating sphere test would be required) and allows the CALiPER program to purchase the product through normal product acquisition channels. If you wish to specify a particular product configuration (or more recent version), that would be allowed if the specific version of the product is commercially available. The resulting test report would include a reference to the initial test along with an indication of the differences between the two product configurations. When results from the retest are available, the initial test report will be updated to include a reference to the additional tests on that product. See the sample Request for Retest Form and Instructions (PDF 68 KB) for more information on submission requirements. Download Adobe Reader.
The U.S. Department of Energy (DOE) is a federal agency working in the public interest. Published information from the DOE SSL CALiPER Program, including test reports, technical information, and summaries, is intended solely for the benefit of the public, in order to help buyers, specifiers, testing laboratories, energy experts, energy program managers, regulators, and others make informed choices and decisions about SSL products and related technologies.
Such information may not be used in advertising, to promote a company's product or service, or to characterize a competitor's product or service. This policy precludes any commercial use of any DOE SSL CALiPER Program published information in any form without DOE's express written permission.
Lighting testing laboratories are instructed to follow test procedures specified in IES LM-79 (Approved Method for the Electrical and Photometric Testing of Solid-State Lighting Products), which tests the luminaire as a whole — as opposed to traditional testing methods that separate lamp ratings and fixture efficiency. There are two main reasons for this: 1) there is no industry standard test procedure for rating the luminous flux of LED devices or arrays; and 2) because LED performance is temperature sensitive, luminaire design has a material impact on the performance of LEDs used in the luminaire. For these reasons, luminaire efficacy (total lumens emitted by the luminaire divided by the total watts drawn by the luminaire's power supply) is the measure of interest for assessing energy efficiency of SSL products, as specified in LM-79.
Do the CALiPER tests take into consideration the luminaire junction temperature, ensuring that the tested product will maintain its expected life?
Thermal management is a key issue for solid-state lighting. There is currently no industry standard that defines a case or board temperature measurement point or other clear mechanism for determining junction temperature for an LED when installed in a luminaire. IES LM-80 (for lumen depreciation measurement) currently describes a thermocouple attachment point on LEDs, but it is unlikely that this measurement point would be accessible once an LED is installed in a luminaire. CALiPER tests luminaires non-invasively primarily following IES LM-79 and also includes temperature measurements on "hot spots" on the luminaires. These external temperature measurements cannot be quantitatively correlated to junction temperatures, but they provide some indication regarding the operating temperatures in the luminaire. CALiPER is also conducting lumen depreciation testing of selected luminaires — particularly those whose thermal management may be insufficient or that may be subject to high "in situ" operating temperatures (such as enclosed fixtures and recessed downlights).
In parallel to the product testing, DOE is working with standards organizations that are addressing lumen depreciation testing and temperature management issues, such as the concept of defining an accessible temperature measurement point in luminaires or another mechanism to measure or correlate to junction temperatures.
Yes, the selection of products is designed to provide benchmarking data with respect to other light source technologies. In some cases, "typical" fixtures and lamps using incandescent or fluorescent sources are purchased and tested for luminaire performance to provide benchmarking examples. When possible, to enable a direct comparison between different light sources, one product is purchased and tested in both an LED version and a halogen version or CFL version of the same luminaire.
Solid-state lighting differs fundamentally from traditional lighting technologies in terms of materials, drivers, system architecture, controls, and photometric properties. A host of new test procedures and industry standards is needed to accommodate these technical differences. To accelerate the development of needed standards for SSL products, DOE facilitates ongoing dialogue and collaboration with key standards-setting organizations, and offers technical assistance in the development of new standards. The CALiPER program provides feedback to these standards efforts. See the DOE SSL Standards Development page for more information.
For a certain percentage of luminaires and replacement lamps in each round of testing, two or more samples are purchased and tested. This enables observation of variability across units of the same product. Furthermore, CALiPER "round-robin" tests are conducted regularly, with the same luminaire or lamp being tested by two or more testing laboratories and, in some cases, repeat testing is conducted by one laboratory. The overall average variation between units of the same product model, between testing techniques (i.e., integrating sphere compared to goniophotometer), and between test results from separate laboratories for CALiPER results to date is limited. Monitoring and analysis of variation and repeatability data is an on-going part of the CALiPER program. This information is shared with standards groups such as the IES SSL Subcommittee of the Testing Procedures Committee to support refinement of testing methods and to identify areas where clarification or additional standards may be needed.
No. CALiPER only tests a small portion of products that are on the market and does not accept submissions or any form of request for testing, so it would be unfair and unjustified to only consider products which have been tested by CALiPER. All manufacturers should have their products tested by an accredited laboratory following IES LM-79, and should make those test results available to specifiers and use those results in product literature (this is basically what CALiPER testing is). While there is always the risk that a manufacturer has submitted "trophy" products for such testing—similar risks can also surround CALiPER testing. CALiPER testing only provides a small snapshot in time. Many factors can be considered in reducing purchasing risks: historic record, long-term knowledge about a manufacturer's credibility, examples shown through CALiPER testing of other products, comparison of LM-79 results to benchmark values for products using other light sources, warranty practices, availability of detailed documentation, etc. It is misguided and in violation of DOE's "No Commercial Use" policy to require that products be tested by CALiPER.