SACRAMENTO - Californians will reach out to a contractor for installing new fenestration fixtures like windows, exterior doors, or skylights hoping to save energy in their home. But, in the case of low-rise residential buildings, there are labeling requirements that contractors need to follow when installing manufactured fenestration products.

According to Section 110.6 of California's 2016 Building Energy Efficiency Standards (Energy Standards), prescribed by the California Energy Commission (Energy Commission), contractors need to make sure the appropriate certification labels are visible upon installation.

Licensed contractors need to look for one of two product Energy Performance Rating labels.

  1. Labels certified by the National Fenestration Rating Council (NFRC); the responsible entity for rating and certifying manufactured fenestration products.
  2. A temporary label which lists the CEC default values.

A manufactured product that is NFRC certified would have both a permanent and non-permanent label. The non-permanent label cannot be removed until a local building department inspector has verified its adequacy; all installations can be put on hold by the inspector if the appropriate labels are not available on site.

Certified NFRC labels should reflect values for the U-factor, Solar Heat Gain Coefficient (SHGC), Visible Transmittance (VT), and Air Leakage.

The NFRC's website has a database of manufacturers who participate in their program, making it easier for contractors to find certified products.

Another option for meeting the Energy Standards criteria for fenestration labels would be to incorporate a temporary label which lists the CEC default values for U-factor, SHGC, and VT; examples and calculations for this option are available in table 110.6-A of the Energy Standards.

It's important to also note that manufacturer-generated performance values do not comply with California's Energy Standards and will not be will not be accepted by building inspectors (i.e. Simulated Performance Alternative" values).

The label options are available in further detail in Section 10-111 of the Energy Standards.

For additional questions on this topic or for more general information regarding California's Energy Standards, contact the Energy Standards Hotline at (800) 772-3300 (in California), or (916) 654-5106 (out of state), or email

Helpful Links:

  • California Energy Commission Regulatory Advisory: Fenestration Labeling
  • 2016 Building Energy Efficiency Standards for Residential and Nonresidential Buildings (Title 24, Parts 1 and 6)
    • Section 110.6 - Mandatory Requirements for Fenestration Products and Exterior Doors
    • 10-111 - Certification and Labeling of Fenestration Product U-Factors, Solar Heat Gain Coefficients, Visible Transmittance, and Air Leakage
  • California Energy Commission (
  • National Fenestration Rating Council (

Archives: 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017