California Code, Government Code - GOV § 15814.30

(a) All new public buildings for which construction begins after January 1, 1993, shall be models of energy efficiency and shall be designed, constructed, and equipped with all energy efficiency measures, materials, and devices that are feasible and cost-effective over the life of the building or the life of the energy efficiency measure, whichever is less.

(b) In determining which energy efficiency measures, materials, and devices are feasible and cost-effective over the life of the building, the State Architect and the Department of General Services shall consult with the State Energy Resources Conservation and Development Commission.

(c) For purposes of this section, “cost-effective” means that savings generated over the life of the building or the life of the energy efficiency measure, whichever is less, shall exceed the cost of purchasing and installing the energy efficiency measures, materials, or devices by not less than 10 percent.