In 2001 more stringent residential code requirements went into effect with the adoption of International Residential Code (IRC) as the statewide residential building energy code. The IRC also incorporates the entire International Energy Conservation Code (IECC) as an alternative energy code for homes with glazing areas of 15% and below.
Texas, like a number of other states and localities across the nation, adopted in its residential building energy code a maximum 0.40 solar heat gain coefficient (SHGC) for fenestration, including windows, glazed doors and skylights. This is true of both new construction and remodeling projects. There are several counties in the Panhandle region where this requirement does not apply.
U-factor code requirements range from 0.37 up through 0.90 depending on which climate zone is applicable to your county and whether it is a new construction or remodeling project. In general, the U-factor requirements are stricter (lower U-factor) in colder climates like the Panhandle region where heating requirements are greater.
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.