There are a variety of energy audits, and they each check different things. We follow the industry standard guides developed by ASHRAE, and they describe audits in levels:
Level 1: a high level walkthrough of your building, looking at things like lighting and other features that you can see with the naked eye and without test instruments or climbing in the ceilings.
Level 2: a more detailed energy audit, where we assess energy bills, create a computer simulation of your building and perform tests to see much energy it should use. We then calculate the savings you could achieve by making various changes. These audits typically cover all the energy systems in the building (eg: lighting, HVAC, plug-loads, data centres, and sometimes process equipment).
Level 3: a very detailed assessment that typically requires us to install temporary meters on your site to measure specific process equipment or areas within your operations.