is owned by the taxpayer, and (C) which is certified to have— (i) a projected annual level of energy consumption after the energy efficiency improvements have been placed in service that is less than the annual level of energy consumption prior to the energy efficiency improvements being placed in service, and (ii) an efficiency ratio of not less than 20 percent. (2) Energy efficiency improvements (A) In general The term energy efficiency improvements means any property installed on or in a qualified building which has been certified to reduce the level of energy consumption for such building, provided that depreciation (or amortization in lieu of depreciation) is allowable with respect to such property. (B) Amounts paid or incurred for energy efficiency improvements For purposes of subsection (a)(2), the amount paid or incurred by the taxpayer— (i) shall include expenditures for design and for labor costs properly allocable to the onsite preparation, assembly, or original installation of the property, and (ii) shall not include any expenditures related to expansion of the building floor area. (d) Certification (1) In general (A) Accredited third party A certification described in this section shall be made by a third party that is accredited by a certification program approved by the Secretary, in consultation with the Secretary of Energy. (B) Guidance A certification described in this section shall be made in accordance with guidance prescribed by the Secretary, in consultation with the Secretary of Energy. Such guidance shall— (i) specify procedures and methods for calculating annual energy consumption levels, and (ii) include requirements to ensure the safe operation of energy efficiency improvements and that all improvements are installed according to the applicable standards of such certification program. (2) Computer software (A) In general Any calculation under paragraph (1)(B)(i) shall be prepared by qualified computer software. (B) Qualified computer software For purposes of this paragraph, the term