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California Title 24 Update Reduces U-Factor and SHGC Requirements

New building energy efficiency standards to go into effect Jan. 1, 2020

As the first state to establish legislation to reduce energy consumption in homes and buildings in 1978, California has paved the way toward greater efficiency ever since. The latest iteration of the California Title 24, Part 6, scheduled to go into effect Jan. 1, 2020, will require that all new buildings achieve Net Zero Energy (NZE) levels by 2020 for residences and 2030 for commercial buildings – once again pushing the envelope in terms of efficiency.

With fenestration accounting for significant impacts on heating and cooling loads, window and door requirements continue to tighten. But by how much?

Here’s what you need to know about the 2019 Title 24 updates for residential buildings:*

  • The maximum U-factor for windows will be 0.30 (previously 0.32).
  • The maximum SHGC in cooler climates will be 0.23 (previously 0.25).
  • The maximum U-factor for doors with less than 25% glazing will be 0.20.
  • Skylight requirements remain unchanged.

The vertical fenestration in commercial buildings will remain the same as the 2016 version of the standard with a maximum U-factor of 0.36 for fixed windows, 0.46 for operable windows, 0.41 for curtain wall or storefront and 0.45 for glazed doors.*

Retooling for increasingly stringent requirements.
If you don’t currently have products that will qualify under the new standard, some design changes will be necessary. Window component changes can have varying impacts on the system. For example, switching from air to argon can lower U-factors by as much as 0.04 and moving from metal-based spacers to warm-edge spacers can reduce U-factors by as much 0.02.

As interest in conserving energy continues to build in California and beyond, retooling now can help you future-proof your business. The best bet is to talk to your suppliers about the best ways to comply with the latest Title 24 standards.

For more information about how Quanex can help, contact me at or to see how we can help you transform your plant, visit

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*SOURCE: American Architectural Manufacturers Association, 2019 California Energy Standards Take Shape, June 2019

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