Auditing Overview

The Basics of an Energy Audit

What's an energy audit?

  • An examination and documentation of anything about the building or space related to energy usage. This includes the building envelope and operation as well as all the equipment or devices that consume energy in a building.

  • An analysis of energy data to understand when and where energy is used, identifying opportunities for energy conservation and efficiency.

  • An evaluation of opportunities and the delivery of a set of recommendations to conserve energy and/or improve energy efficiency, including a cost-benefit analysis.

What does an energy audit accomplish?

  • Identify potential energy savings 

  • Address comfort problems for building occupants

  • Gauge the impact and payback of installing renewable power systems​

  • Evaluate the potential of utility incentives including rebates and demand response programs

  • Understand and document the performance of the building in preparation for building commissioning

Source: PG&E Pacific Energy Center course, "Energy Auditing Techniques for Small Commercial Facilities" 2019.

 

ASHRAE Building Energy Audits: Level 1-3

The American Society of Heating, Refrigeration and Air-Conditioning Engineers, commonly referred to by its acronym ASHRAE, defines the different levels of audits by the amount of effort required:

  • Preliminary Energy-Use Analysis

  • Level 1- Walk-through Survey

  • Level 2- Energy Audit Survey and Analysis

  • Level 3- Detailed Analysis of Capital-Intensive Modifications

A Preliminary Energy-Use Analysis includes a calculation of the building's energy use intensity (in kBtu/square foot) and benchmarking this energy use intensity against buildings of the same type. 

A Level 1 audit expands to include a walk-through of the building and delivers energy efficiency recommendations with rough costs and savings and identifies capital projects.  

A Level 2 audit is a more detailed analysis and expands to include an energy survey and engineering analysis. The deliverables include a breakdown of end-uses, cost/savings for energy efficiency measures, and operations and maintenance changes. 

A Level 3 audit is a refined analysis and expands to include additional measurements, testing, modeling, and life-cycle cost analysis to inform decision making.  

Source: ASHRAE, "Procedures for Commercial Building Energy Audits, Second Edition" 2011.