Energy Audits

Effective management of energy-consuming systems can lead to significant cost and energy savings as well as increased comfort, lower maintenance costs, and extended equipment life. A successful energy management program begins with a thorough energy audit.

The energy audit evaluates the efficiency of all building and process systems that use energy. The energy auditor starts at the utility meters, locating all energy sources coming into a facility. The auditor then identifies energy streams for each fuel, quantifies those energy streams into discrete functions, evaluates the efficiency of each of those functions, and identifies energy and cost savings opportunities.

Audit activities, in general order, include:

The report documents the use and occupancy of the building and the condition of the building and building systems equipment. The report also recommends ways to improve efficiency through improvements in operation and maintenance items (O&M), and through installation of energy conservation measures (ECM).

Degrees of Thoroughness

Audit levels, in order of increasing complexity are:

Level 1- The walk-through audit. The walk-through audit is a tour of the facility to visually inspect each system. The walk-through includes an evaluation of energy consumption data to analyze energy use quantities and patterns, as well as to provide comparisons with industry averages, or benchmarks, for similar facilities. This is the least costly audit, but a level 1 audit can yield a preliminary estimate of savings potential and a list of low-cost savings opportunities through improvements in operational and maintenance practices. The level 1 audit information may be used for a more detailed audit later if the preliminary savings potential appears to warrant further auditing activity.

Level 2- Standard audit. The standard audit quantifies energy use and losses through a more detailed review and analysis of equipment, systems, operational characteristics, and on-site measurements and testing. Standard energy engineering calculations are used to analyze efficiencies and calculate energy and cost savings based on improvements and changes to each system. The standard audit will also include an economic analysis of recommended ECMs.

Level 3- Computer simulation. The level 3 audit is the most expensive level of energy audit and is most often warranted for complex facilities or systems. The audit includes more detailed energy use by function and a more comprehensive evaluation of energy use patterns. Computer simulation software is used to predict building system performance and accounts for changes in weather and other conditions. The goal is to build a base for comparison that is consistent with the actual energy use of the facility. The auditor will then make changes to improve the efficiency of various systems and measure the effects compared to the baseline. This method also accounts for interactions between systems to help prevent overestimation of savings.