The minimum state-mandated code for single-family homes is Chapter 11 of the 2015 International Residential Code. The applicable code for other residences and commercial and industrial buildings is the 2015 International Energy Conservation Code.
These energy codes are effective statewide. Texas is a "home rule" state, however, allowing local jurisdictions to adopt amendments to the codes. To amend the state code in non-attainment and affected counties, Energy Systems Laboratory at Texas A&M University at the request of a municipality or county must first determine whether the amended code is as stringent as existing state codes. Code changes that are determined to be as stringent or more stringent than state code may be adopted as a local rule.
Local jurisdictions are responsible for building energy code implementation and enforcement.