Commercial Energy Audits

Having an energy audit completed for your commercial facility can help you gain valuable insight into the most cost-effective ways to improve your building’s energy use and reduce your energy bills. The options available for energy audits vary in depth, complexity, and cost, depending on the potential at a specific site for energy and cost reductions and the objectives determined by the customer. According to the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards, there are three levels of energy audits as summarized in the chart below. When you are preparing to have an energy audit completed, it is recommended to have at least 2 years of fuel usage and cost data available so the auditor can create a more accurate report tailored for your building.

If you are interested in a commercial energy audit, consider taking advantage of HG&E's Commercial Energy Conservation Program, which provides financial assistance at 0% interest for energy audits as well as various energy efficiency and electrification projects. Qualifying industrial customers may be eligible for a free facility audit through the UMass Industrial Assessment Center, which is supported by the U.S. Department of Energy. 

The table below summarizes the basic characteristics of each level:

Audit Type

Brief Description of Audit Type/Level

Level 1

  • Brief on-site survey and walk-through of the building(s).
  • Review of facility utility bills.
  • Cost and savings analysis of low-cost/no-cost Energy Conservation Measures (ECMs).
  • Identification of potential capital improvements for further consideration.

Level 2

  • More detailed building survey.
  • Breakdown of energy use.
  • More in-depth savings and cost analysis of identified ECMs.
  • Identification of ECMs requiring more thorough data collection and analysis (Level 3).

Level 3

  • Focus on capital-intensive projects identified during the Level 2 audit.
  • More detailed data gathering and field analysis.
  • More in-depth engineering analysis.
  • Cost and savings projections/calculations with a high level of detail.

ASHRAE Audit Details by Level

The Level 1 audit can be referred to as a scoping audit, simple audit or walk-through audit and is the most basic. It involves minimal interviews with site operating personnel, a brief review of facility utility bills, and a walk-through of the facility, for the identification of obvious areas of inefficiencies or energy waste.  Based on the findings from the walk-through, the auditor will then furnish a report detailing low-cost/no-cost Energy Conservation Measures (ECMs) and potential capital improvements for further study. Typically, a Level 1 audit will only uncover major problem areas. Corrective measures are briefly described, and quick estimates of implementation costs, potential operating cost savings, and simple payback periods are provided. This level of detail, while not necessarily sufficient for reaching a final decision on implementing proposed measures, is sufficient to help prioritize energy efficiency projects and to assess the need for a more detailed audit.

A Level 2 audit will include the preliminary ASHRAE Level 1 analysis, but also includes more detailed energy calculations and financial analysis of proposed energy efficiency measures. The financial analysis or Life Cycle Cost Analysis provides the facility owner with comprehensive understanding of the financial benefits of implementing specific energy efficiency measures. Utility bills are collected for a 24 to 36 month period to allow the auditor to evaluate the facility’s energy/demand rate structures and energy usage profiles. This type of audit identifies all energy conservation measures appropriate for the facility given its operating parameters. A detailed financial analysis is performed for each measure based on estimated implementation costs, site-specific operating cost savings, and the customer’s investment criteria. A Level 2 Audit should provide sufficient detail is to justify implementation of ECMs.

This level of analysis focuses on the potential capital-intensive projects identified by the Level 2 analysis and involves more detailed field data gathering and a more in-depth engineering analysis. It provides detailed project cost and savings calculations with the high level of confidence required for major capital investment decisions. This audit can be referred to as a detailed audit or comprehensive audit.  It expands upon the Level 2 audit by providing a model of energy use characteristics of both the existing facility and all energy conservation measures identified. The building model is calibrated using actual utility data to provide a realistic baseline against which to compute operating savings for proposed measures. A Level 3 audit provides an understanding of not only the operating characteristics of all energy consuming systems, but also the situations and behaviors that may cause load profile variations on both an annual and a daily basis. Existing utility data is often supplemented with sub-metering of major energy consuming systems and monitoring of system operating characteristics.


Contact Michael Curtin
Technical Support Engineer - Key Accounts

Tel: (413) 536-9319