Energy auditors evaluate energy use patterns. They look at both home and commercial buildings, and recommend ways buildings can use less energy.

Energy auditors perform many types of audits. Some are small audits of homes and offices, while others are large, such as those of schools or industrial complexes. The amount of detail on the audit also varies. Some are in-depth and take more time and expertise, while others are quick, walk-through audits.

Home energy auditors look at the outside characteristics of a home, such as its size, the number of windows and doors, if there are skylights, and the type of siding or exterior. They look at the patterns of the people who live there. They ask questions, such as, ""Are the people there during the day?"" ""Is there a room that never gets used?"" ""What source of heat is used during the winter?"" The auditor does a room-by-room analysis. They use the same process when inspecting a non-residential building. They look for patterns such as how many people work in the building and what hours it is unoccupied. They look for ways to reduce electricity use.

Energy auditors use different types of tests during the audit, such as the blower door test and a thermographic scan. They also analyze the client's utility bills (water and electricity) for the previous year. After the audit, auditors write a report that describes the customer's energy use patterns and offers suggestions of ways to use less energy. Energy auditors use software to develop recommendations for improvements.

Once a project is complete, the auditor checks that the work meets safety and design standards. They make sure the new equipment, like water heaters, windows, and insulation, matches the designs.