Fenestration Review

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NFRC announces new software for simulation and certification

September 20, 2022  By NFRC

The NFRC Board has approved Lawrence Berkeley National Lab (LBNL) WINDOW 7.8.55 and THERM 7.8.55 for immediate use. WINDOW 7.8 / THERM 7.8 has been extensively tested by multiple simulation laboratories. In the process, numerous bug fixes and enhancements were implemented, and the software is now ready for full implementation. This bulletin is to announce the implementation schedule for use of WINDOW 7.8 / THERM 7.8 for NFRC simulation and certification purposes.

Item #1: Use of WINDOW 7.8.55 & THERM 7.8.55

WINDOW 7.8.55 / THERM 7.8.55 may be used beginning on October 1, 2022. Beginning April 1, 2023, WINDOW 7.8.55 / THERM 7.8.55 shall be the only approved software for NFRC 700 ratings for new certifications, recertifications, or revisions/addendums

1.   Product lines uploaded to the Certified Products Directory (CPD) prior to the date of this bulletin shall be acceptable and do not require any remodeling using WINDOW 7.8 / THERM 7.8.


2.   Reissues and revisions of existing product certification simulation reports shall be handled in the following manner:

  • Reissues containing only a company and/or product name change may continue to the certification expiration date and require no update.
  • Reissues that include new simulated product options without shading systems, may continue to use WINDOW 7.4 / THERM 7.4 or WINDOW 7.7 / THERM 7.7 until the sunset date. (See Item #2).
  • If new simulated product options containing shading systems are added to a reissued or revised report, the shading system options requiring use of the CGDB shall be rated using WINDOW 7.8 / THERM 7.8.
  • After the sunset date, all new simulated product options added to a reissued or revised report shall use WINDOW 7.8 / THERM 7.8.

Item #2: Sunset of WINDOW 7.4/THERM 7.4 & WINDOW 7.7.10/THERM 7.7.10

WINDOW 7.4 / THERM 7.4 and WINDOW 7.7 / THERM 7.7 shall no longer be used after March 31, 2023. Blinds in the up and stacked position, which do not require use of the CGBD may be rated using either WINDOW 7.4 / THERM 7.4 or WINDOW 7.7 / THERM 7.7 until the sunset date.

Shading system product options using the CGDB shall use WINDOW 7.8.55 / THERM 7.8.55 beginning Oct. 1.

NFRC certification of products modeled in accordance with the Component Modelling

Approach (CMA) for NFRC 705 certification within CMAST shall continue to use

WINDOW 6.3 / THERM 6.3. CMA is the only program not affected by the sunset date.

Item #3: WINDOW 7.8.55/THERM 7.8.55 New Features 

Additional information related to new features and changes to the software can be located on the NFRC Community and the Lawrence Berkeley National Laboratory websites.

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