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Frequently Asked Questions

General and Certification FAQs

Commercial Program FAQs


If you have a question not answered by the FAQs above, please send us an email at info[at]

General and Certification FAQs

Why does NFRC exist?

Back in the early 1980s, window, door and skylight manufacturers introduced new technologies designed to improve the energy performance of their products. Unfortunately, consumers had no good way to judge the effectiveness of these technologies, or to compare the performance of different products accurately and reliably. With the federal government beginning to think about establishing an independent agency to rate fenestration energy performance, the industry decided to take the initiative and formed NFRC in 1989.

Is NFRC affiliated with the government?

No. NFRC is an independent 501(c)3 nonprofit organization, formed to service the public good through education and research . The National Energy Policy Act of 1992 directs the U.S. Department of Energy (DOE) to monitor and support NFRC's activities, and DOE provides a small amount of funding each year that is used mainly to support NFRC's research efforts. A DOE representative also sits on the NFRC Board of Directors as a non-voting member.

How many manufacturers certify their products?

The Directory includes energy performance ratings for over 1.67 million product options from more than 500 manufacturers (program participants), and the list of participants grows every month.

Why do manufacturers certify their products?

Mostly because they recognize that energy performance is very important to their customers, and they want to provide them with accurate and reliable information. In addition, NFRC Certified Products carry the NFRC Temporary Label that provides building inspectors the ability to confirm that the product meets or exceeds local energy code requirements. NFRC certification is strictly voluntary, although to meet the criteria for becoming an ENERGY STAR ® product according to the federal government, a product must be NFRC-certified.

How does the NFRC Product Certification process work?

How does NFRC develop its rating system and programs?

The NFRC Board of Directors and Membership have established seven standing committees to coordinate the development and implementation of the rating system:

Is NFRC working on any additional energy performance ratings?

Yes. Right now, fenestration manufacturers can rate the U-Factor, solar heat gain coefficient (SHGC), visible transmittance (VT), air leakage (AL), and condensation resistance (CR) of their products through the NFRC system. The Council has also developed rating and labeling procedures for window film attachments, internal or between the glass blinds and shading devices, and dynamic glazing products that change tint in response to temperature, sunlight, or electric charge. The Certified Products Directory is expanding to include these ratings as they become available. NFRC is currently considering such energy ratings as ultraviolet light/fade protection, and overall comfort.

Commercial/Site Built Program FAQs

Does NFRC have certified site-built assemblies included on its web page?

Yes.  There are curtain wall systems entitled "Glazed Wall Systems" listed in the online Certified Products Directory, whose currency is maintained in real time.

What is the amount of time involved in obtaining product certification for a site-built project?

Depending on the complexity of the building project (i.e., the number of various fenestration systems and product lines on a building envelope) it will take on average approximately 100 days to obtain a Label Certificate. (see Appendix 1- Guidelines for Site-Built Fenestration Systems)

How does the responsible party (i.e., architect, contractor) obtain a label certificate for products that are already certified by NFRC?

If the curtain wall manufacturer is the responsible party, he/she will already have the Label Certificate for a specific product that will be used on a project.

However, for the glazing contractor or architect there are three paths:

  1. They can provide the test and simulation for specific products on a project;

  2. They can review the Certified Products Directory and request a specific certified product from the supplier or contractor.  They then contact an IA and inform the IA that they will be using certified system #xxx.  The IA then obtains all pertinent data and issued a label certificate to the contractor or architect.  Typically test reports for the specified certified product are re-issued under the contractor's or architect's name due to changes in glazing type.

  3. They can request that a supplier provide a test and simulation report for a product to an accredited lab in accordance with NFRC 100.  Those test reports are good for four years and will have to be reissued in the contractor's or architect's name if there are glazing substitutions.  The contractor/architect is still the responsible party and the IA must review ALL information prior to issuing a Label Certificate.  The product is not considered certified until a license agreement is signed with NFRC, certification authorization is obtained, and a label certificate is generated.

How can one tell that the certified products that are being installed on a building are the same as the products for which a responsible party has a Label Certificate?

All the information about the products on the building envelope is contained in the Label Certificate for a building inspector's or code official's use, if needed or desired. The label certificate is posted on site. If desired or required a code official could request a Label Certificate prior to issuing a building permit.  NFRC-licensed IAs inspect the offices of the responsible party to assure that the fenestration schedule and drawings submitted for the simulation and test reports match the original specifications and drawings for the site-built project.  If they do not, certification is withdrawn.


How does ENERGY STAR fit in?

The Energy Star Program is for residential applications, three stories or fewer. ENERGY STAR for Windows, Doors, and Skylights is a program only for residential applications, meaning non-commercial buildings or residential structures under three stories. Commercial windows, doors, and skylights require a separate program because of the different structural, durability, and wind load performance requirements.  Look for information on NFRC's Component Modeling Approach (CMA) for Commercial applications coming soon.

If you have a question not answered by the FAQs above, please e-mail NFRC at info[at]