Code Requirements

Texas has adopted the 2015 IECC and IRC, which specifies prescriptive values for U-factor and SHGC for residential windows by climate zone.

Solar Heat Gain Coefficient (SHGC)

Texas, like a number of other states and localities across the nation, adopted in its residential building energy code a prescriptive maximum 0.25 solar heat gain coefficient (SHGC) for fenestration, including windows, glazed doors and skylights in all construction in climate zones 2 and 3, and a 0.40 SHGC in climate zone 4. This applies to both new construction and remodeling projects. Although 0.25 is the maximum, SHGC values lower than 0.25 are preferable for optimal energy savings.


U-factor code requirements range from 0.35 to 0.65 depending on which climate zone is applicable to your county and which type of fenestration is being installed. In general, the U-factor requirements are stricter (lower U-factor) in colder climates like the Panhandle region where heating requirements are greater. We recommend a 0.35 maximum U-factor statewide for optimal energy savings.

For more specific information on code requirements and how to select code compliant windows products for new construction and replacement projects, visit the Code Requirements.