What is a NFRC window label & why do I need it?
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The 2016 California Title-24 Building Energy Standards require that the efficiency of windows and doors be documented in the Title-24 compliance calculations using one of two allowable methods. NFRC or the default assumptions. We’ll address both methods:
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NFRC:
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The NFRC (National Fenestration and Rating Council) is a non-profit organization which oversees and sponsors an energy efficient certification and labeling program to document the thermal performance of windows, doors, and skylights.
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California’s Title-24 Energy Code requires that U-factor, SHGC values used in Title-24 compliance reports be backed up by NFRC documentation as well as a temporary label on the actual window/door available for inspection during construction. The temporary label shows the U-factor and SHGC for each rated window and door. This label must also show that the window meets the air infiltration criteria. This temporary label must not be removed before inspection by the building official at final inspection. There also is a permanent label is usually inscribed on the spacer, or etched on the glass, or engraved on the frame and includes a number or code to allow tracking back to the original performance information on file with the NFRC.
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Default tables:
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Many times window and door manufactures have not gone thru the NFRC testing procedure or the windows/doors are essentially site built which makes it impossible to test the actual performance of these windows and doors. In this case your only option is the default assumption method.
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This involves modeling your project for Title-24 compliance using the C.E.C.’s default U-factors and SHGC values from the default tables (Tables 110-6-A and 110-6-B in the Title-24 standards). These default values are assumptions based on window and framing types. If the windows and doors are using these default tables for their performance numbers (U-factor & SHGC) they also must have a label that uses the phrase “CEC Default U-factor” and “CEC Default SHGC” in front of or before the U-factor or SHGC. These phrases cannot be simply used in a small print footnote on the label.
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If default performance values are used then the Title-24 energy calculations also must use the same values in the compliance report. Most windows and and door that are tested and labled by the NFRC have U-factors and SHGC values that are significantly better than the default values from the tables. This can often make the difference between passing and failing the Title-24 energy code standards so it is to your advantage to use the NFRC testing data in the Title-24 compliance calculations rather than using the default numbers from the tables.
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Overlooking this crucial item in the Title-24 report can result in huge problems during construction. It is not uncommon for the installing window contractor to bid on the project without ever consulting the approved Title-24 energy code report. If the Title-24 report is calling out for NFRC compliant windows and doors and the contractor orders and installs non-NFRC products the project is in real trouble. During the course of construction the building inspector normally will go thru the project looking for the NFRC stickers on the windows/doors and compare them with the approved Title-24 Certificate of Compliance. If there are discrepancies noted, or the windows/doors have no NFRC stickers, or are site-built then the builder must either revised the Title-24 compliance report to demonstrate that the project will comply with the default assumptions in table 110-6 (U-factor and SHGC) or replace the windows/doors with NFRC compliant ones.
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The problem is that often times there is no margin within the Title-24 analysis to absorb the significant penalty for using the default tables for U-factor and SHGC values. This penalty is significant especially with metal framed windows/doors.
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The lesson is clear, Title-24 compliance should be a central topic for discussion with window/door suppliers and installers when they are bidding on the project, not pushed off with vague assurances which later could bring the project to a standstill when this comes to light during construction.
