NFRC logo


NFRC operates a research program to determine ever improving methods to rate the energy performance of windows, doors and skylights. Since 1989, NFRC and the U.S. DOE have invested an estimated $3 million in fenestration rating research to ensure the most accurate ratings possible. Currently, the NFRC has a $2 million cooperative agreement with the US DOE titled, Fenestration Rating Development and Research to develop new ratings and improve on existing ratings through 2016.

NFRC has also worked with the US State Department to harmonize fenestration energy ratings in China. A recently completed $500,000 project titled, Building Energy Performance Certification, enabled NFRC to implement part of its energy rating system with Chinese building authorities. In 2011, NFRC completed a $100,000 research project titled, Energy Saving Windows in APEC Economies, for the Asia Pacific Economic Cooperation (APEC) and published its findings on the APEC web site.

NFRC’s Research Program requires submission of a summary page to the membership for consideration and a vote. If approved, the summary page becomes a request for proposal (RFP) and is again voted on by membership. Approval of the RFP by membership leads to issuance of the RFP for bidders and award of the project. research image NFRC volunteer members monitor the project and report findings to membership for integration into the NFRC energy rating process. The NFRC Research Program Manual (NFRC 703) provides details on this process. Using this process, NFRC has several successful research projects contributing immediately to improved NFRC ratings including:

  1. Attached Awning Rating Research-Provided fundamental research to begin the process to rate attachment energy performance.
  2. CMA Condensation Resistance (CR) Rating Research-led to a new method to rate CR in commercial window products.
  3. Door Rating Simplification-Significantly improved the ability to communicate door energy performance.
  4. Tubular Daylighting Devices Rating-created a method to rate the U-factor of Tubular Daylighting Devices.
  5. WINDOW6-THERM6 Validation Research-Investigated U-factor and SHGC ratings for various attachment products to determine new simulation and testing methods for these products and enable full energy ratings for use in building energy codes.
  6. Three Dimensional Effects of Heat Transfer on Fenestration Ratings-Proved that three dimensional effects are limited in fenestration ratings.
  7. SHGC for 7 Glazing Types in Combination with 7 Interior Window Attachment Products-Proved the significant energy saving capability of exterior window attachments and demonstrated interior window attachment benefits as well.
  8. CMA Non Standard Product Research-Investigated several unique window types to confirm CMA energy rating capabilities.
  9. Complex Product VT Ratings Research-Improved Visible Transmittance measurement techniques for tubular daylighting devices.
  10. Spectral Weighting Function Research-Provided a method to implement a new solar spectrum into existing energy simulation algorithms to increase accuracy of all NFRC ratings.
  11. Gas Permeability Research-Investigated various reasons for gas fill leakage in insulating glass units.
  12. Thermal Comfort Rating Research-Determined a method to rate fenestration based on occupant comfort.
  13. Non Planar Fenestration Rating Research-Developed a method to simulate the energy performance of non-planar skylights (domed skylights).

For more information view the document that guides the NFRC Research Program, NFRC 703.