Energy ratings
What is an NFRC rating?
The National Fenestration Rating Council is the independent, non-profit body behind the energy label on windows and glass doors in the United States. Its ratings put every product on the same scale — measured on the whole assembly, not just the glass — which is why architects, energy consultants, and code officials treat NFRC values as the reference numbers for fenestration performance.
On the label
Three numbers carry most of the conversation.
- U-Factor
- The rate of heat transfer through the entire assembly — glass, frame, and edges together. Lower is better insulated. Typical code conversations start here.
- SHGC
- Solar Heat Gain Coefficient — the fraction of solar energy that makes it through the glazing, from 0 to 1. Lower values reject more heat; the right target depends on climate and design.
- Visible Transmittance
- How much daylight passes through, from 0 to 1. High VT with controlled SHGC is the balance most glass-forward architecture is chasing — light without the heat.
Why configuration matters
The frame and the glass
rate together.
A center-of-glass number from a glazing brochure is not a product rating. NFRC values are whole-product: the same ORLUTI frame carries different ratings depending on the glazing package — Low-E coating, insulated build-up, gas fill, laminated plies, spacer. That is also why project teams should verify values for the specific configuration on their schedule rather than quoting a generic datasheet.
NFRC-rated configurations are available across the ORLUTI window and sliding-door range. Tell us the opening sizes, orientation, and code targets, and the engineering desk returns the system and glazing configuration with the performance data your energy consultant needs — project-specific U-Factor and SHGC based on system and glazing selection.
Performance and compliance vary by system, glazing configuration, project location, and applicable code requirements. Contact ORLUTI for project-specific documentation.
Building in California? NFRC values are the inputs — Title 24 is the test they feed.
Read the Title 24 guide →