An energy audit is an inspection survey and an analysis of energy flows for energy conservation in a building. It may include a process or system to reduce the amount of energy input into the system without negatively affecting the output. In commercial and industrial real estate, an energy audit is the first step in identifying opportunities to reduce energy expense and carbon footprint.

The term energy audit is commonly used to describe a broad spectrum of energy studies ranging from a quick walk-through of a facility to identify major problem areas to a comprehensive analysis of the implications of alternative energy efficiency measures sufficient to satisfy the financial criteria of sophisticated investors. Numerous audit procedures have been developed for non-residential (tertiary) buildings (ASHRAE; IEA-EBC Annex 11; Krarti, 2000). Audit is required to identify the most efficient and cost-effective Energy Conservation Opportunities (ECOs) or Measures (ECMs). Energy conservation opportunities (or measures) can consist in more efficient use or of partial or global replacement of the existing installation.

Types of energy audit

• The analysis of building and utility data, including study of the installed equipment and analysis of energy bills.
• The survey of the real operating conditions.
• The understanding of the building behaviour and of the interactions with weather, occupancy and operating schedules;
• The selection and the evaluation of energy conservation measures.
• The estimation of energy saving potential.
• The identification of customer concerns and needs.