An energy audit is an inspection and analysis of energy usage of a commercial or residential building to conserve energy. It is the first step in identifying opportunities to reduce carbon footprint and energy costs in commercial real estate properties.
The primary goal of a residential building is to reduce energy consumption while maintaining or improving comfort, safety, and health of tenants. Besides identifying the sources of energy use, the purpose of an audit in a building is to prioritize the energy usage from the most to least cost-effective possibilities of energy savings.
An Audit identifies various facility upgrade opportunities and can be used as an effective planning tool to ensure the energy usage savings are made and sustained in the long term. The aim is to have all defined improvement projects “payout” in two to four years, which converts to a ROI of between 25 - 50%. A common expected starting point of an accredited Energy Audit results in recommendations for savings between 5 - 25%.
Cathy Zheng a Professional Engineer in Ontario and Energy Auditor with CZ Consulting indicates;
“In the nutshell; an energy audit is a recommended first step planning tool, that provides a road map for the management (financial and operation) to decide where to invest their capital next.”
Energy Audit Phases
There are typically three phases to an Energy Audit, depending on requirements:
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Investigation Phase
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Monitoring Phase
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Analysis & Reporting Phase
This involves the auditor collecting historic (3 years) and current energy consumption, energy provider contracts, size of the building, people strength, producing output, working hours, consuming power like lighting and other equipment with their specifications, current energy management protocols and systems.
In this phase the auditor inspects the operation of different machinery items and tracks key performance parameters like the temperature and humidity levels, ventilation rate, electrical & gas load stats, etc. It may also include watching employees managing the equipment to understand the operational practices and maintenance procedures.
The auditor looks at the energy efficiency of the building related to the production/output, emissions, power tariff, ABGR energy star rating, and peak demand management.
Types of Energy Audits
1. A Walk-Through Audit
These audits are typically undertaken for smaller sites with lower energy spending. It provides an overview of energy performance and identifies low-cost energy saving opportunities.
Type 1 audits are meant to assess building energy efficiency and determine areas of possible improvement as well as the need for other kinds of audit. This kind of audit is primarily based on visual verifications from specialists and a detailed study of the equipment, energy consumption patterns, and basic operating data. Type 1 audits can usually be completed in a month.
2. Detailed/ General Energy Audit
General energy audits include an analysis of energy performance to identify opportunities for a site in detail. It provides a detailed savings and cost analysis for identified projects using calculated energy usage according to the size, load, efficiency, hours, etc.. It is the most popular audit type for properties. Type 2 audits are generally completed in 2-3 months and need to be revised every 3-5 years.
3. Investment Grade Audit
Audits of this type are usually focused on one process or subsystem level, such as compressed air or lighting or building management systems, rather than a whole site.
Investment Grade audit is a longer process because large amounts of energy data over multiple shorter periods are used to track energy usage at a granular level. These audits are most suitable for big buildings as they offer the highest accuracy and are done with a specialized modeling software. Time frames for are typically a minimum of 6 months but vary based on the needs of the client. These audits include onsite measurements to monitor energy data over a period long enough to identify various operating conditions and relevant variables.
