NFRC Labels and Title 24 Window Approval
The label is how a window is approved on site. The temporary label lists the window's U-factor, SHGC and visible transmittance and certifies its air leakage, and it must stay on until the inspector has seen it. A permanent mark lets the rating be traced back to the NFRC directory.
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The temporary label
Under Section 10-111(a)1, every manufactured window and exterior door carries a clearly visible label giving U-factor, SHGC and VT, and certifying the 0.3 cfm per square foot air leakage limit. No other values may appear on it, and it follows NFRC 700 formatting. Section 110.6(a)5A bars removing it before the enforcement agency inspects.
The permanent label
A rated product also carries a permanent mark, either a stand-alone label, a tab on the maker's label or marks and etchings. It must let anyone trace the product to its certification on file. The manual lists the spacer, the glass or the frame as places it may sit. NFRC is the supervisory entity and keeps the Certified Product Directory.
How the department reads it
The inspector verifies window U-factor and SHGC at the rough-frame visit by comparing the label with the compliance documents. The 2022 manual tells inspectors that if no labels are on site, further window installation should not proceed until proof is produced. Visible transmittance is informational: low-rise residential has no minimum. A rating applies to the whole product, frame included, for one typical size in the product line.
Site-built and field-built windows
- Site-built units carry an NFRC label certificate instead of a temporary label.
- Field-fabricated windows are exempt from labelling but must use the default Tables 110.6-A and 110.6-B and be caulked and weatherstripped.
- Windows removed and reinstalled in an alteration are excepted from Section 110.6(a).
A default label
A product not rated by NFRC may carry a label reading "CEC Default U-factor" and "CEC Default SHGC" followed by the table value, and a thermal-break default must also state "Meets Thermal Break Default Criteria". What those defaults cost is on what happens with no NFRC label.
Installers can see the paperwork side on our window installer page, the numbers on new windows and Title 24, and the sequence in the replacement checklist. Our residential reports list the values the label must match.
Common Title 24 Questions
- When is Title 24 required for a home?
- Does a remodel need Title 24?
- Does a room addition need Title 24?
- What plans are needed for a residential Title 24 report?
- How much does a residential Title 24 report cost?
- How long does a residential Title 24 report take?
Frequently Asked Questions
The Energy Commission names NFRC as the supervisory entity. Independent certifying organizations licensed by NFRC certify the ratings that appear on the label.
Not before the building department has inspected. Section 110.6(a)5A prohibits removing the temporary label until then.
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View all Windows and Doors guides → · Windows and Building Envelope · Title 24 guide