Life cycle costs are to be used when contracting for major energy-consuming products. In determining life cycle costs, the state may consider the acquisition cost of the product, its energy consumption and the projected cost of energy over the useful life of the product, and the expected resale or salvage value of the product.

Except where prohibited by private act or state law, the county shall adopt the energy efficiency standards and life cycle costing employed by the state. The county may develop and adopt its own energy efficiency standards, provided they are more stringent than the state’s. T.C.A. § 12-3-901 et seq. (formerly § 12-3-601 et seq.)