The Measurement and Verification (M&V) of the performance of mechanical systems is a fundamental element in Performance Contracting, LEED Certification and Commissioning and Retro-Commissioning. If performance is not measured, there is no way of knowing how a building is performing or how much the performance has improved after work has been done. EE&D has extensive experience in M&V in many types of environments. As a subcontractor to the National Renewable Energy Lab (NREL), EE&D was part of the M&V working group to develop a standard M&V Plan format for Energy Savings Performance Contract projects at Federal facilities. The result of this work was the publication of the M&V Guidelines for Federal Projects.