ASHRAE Audit Level 1 2 and 3: What’s the Difference?

An energy audit is the first step to making your commercial facility more energy efficient. It identifies how, when and where energy is being used in a building.  It also identifies areas where energy efficiency upgrades will produce energy savings. ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) defines best practices for energy audits for those providing energy services. ASHRAE Audit Levels 1 2 3 have standards, which vary in depth.

Preliminary Energy Use Analysis: This is the most basic energy audit and involves an analysis of historic energy use and costs. Energy use is typically benchmarked or compared against similar buildings to determine if further engineering study and analysis are likely to produce significant energy savings.

ASHRAE Audit Level 1 – Walk-Through Analysis: This energy audit is the basic starting point for building energy optimization, and involves interviews with select facility staff, a review of utility bills or other operating data and a walkthrough of the facility. Often a Preliminary Energy Use Analysis and Walk-Through Analysis are completed in tandem. The goal is to identify glaring areas of energy inefficiency. The data is compiled and used to complete a preliminary report detailing low-cost/no-cost measures and potential capital improvements for further study in subsequent audits. This level of detail is adequate for prioritizing energy efficiency projects and to assess whether a more detailed audit is necessary.

ASHRAE Audit Level 2 – Energy Survey and Analysis: This includes the ASHRAE Level 1 analysis, but adds detailed energy calculations and financial analysis of proposed energy efficiency measures. Energy consumption is broken out by end-use, identifying areas which present the greatest efficiency opportunities. Utility rates are analyzed to determine if there are rate change opportunities, and key building representatives are interviewed for insights into building operational characteristics, potential problem areas, and to define financial and non-financial goals of the audit. This level of detail is adequate to justify project implementation.

ASHRAE Audit Level 3 – Detailed Analysis of Capital Intensive Modifications: This focuses on an engineering analysis of the potential capital-intensive projects identified in the ASHRAE Level 2 Analysis. There is more detailed field data gathering at this time and more rigorous analysis. Existing utility data is supplemented with sub-metering of major energy-consuming systems and monitoring of those system’s operating characteristics.

This provides a realistic baseline to compare energy and operating savings of the proposed measures pre- and post-energy project implementation. The Level III audit is typically reserved for complex commercial and industrial buildings.

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