In conjunction with the advisory group under section 701.509, the department shall update the minimum energy efficiency standards in section 701.503 not less than once every three years beginning from the date the standards were first promulgated by rule. The purpose of any such update shall be to keep the state standards current with technological advancements and industry practices with regard to energy efficiency, while also giving due consideration to consumer and environmental costs and benefits. The department shall strive to have the standards achieve greater energy efficiency over time in a prudent and reasonable manner. Standards shall not be more stringent than required by the federal energy star program requirements, if such requirements are applicable.