Under Local Law 87, the Association of Energy Engineers' Certified Building Commissioning Firm, Certified Building Commissioning Professional, and Existing Building Commissioning Professional certifications are approved retro-commissioning certifications, and the Certified Energy Manager and Certified Energy Auditor certifications are approved for energy auditing. The City of San Francisco's Department of the Environment now recognizes a Certified Energy Manager, Existing Building Commissioning Professional, and Certified Building Commissioning Professional with at least two years' experience as qualified to provide energy auditing services. Under the city's Environment Code Chapter 20 Existing Commercial Buildings Energy Performance Ordinance, an energy audit is required every five years.