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What is an Energy Audit?

An Introduction to Building Energy Audits

An energy audit is an assessment of the energy efficiency of a building. It identifies opportunities to save energy, reduce costs and improve the value of a property. Energy audits can also make a building more comfortable and safer for its occupants. Whether for a new construction project, major building renovation, commercial interior, or existing building, energy audits can help property owners make their buildings smarter and more environmentally-friendly.

During an energy audit, a qualified inspector will take a comprehensive look at the energy consumption data associated with a commercial building, as well as the energy and resource consuming infrastructures, to identify fiscally responsible, sustainable energy efficiency measures (EEMs) that reduce energy usage and carbon emissions. Typically, the process used to identify EEMs consists of the following steps:

  • Review of building plans and specifications
  • Building walkthrough and survey
  • Interview with building engineer
  • Analysis of utility data
  • Generation of building energy consumption model

There are different kinds of energy audits with different levels of comprehensiveness, so commercial building owners may need to think about their end goals before deciding which kind of audit is best for them.  The American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) has defined three levels of energy evaluations: 1) Level I “Walk Through Assessment” 2) Level II “Energy Survey and Analysis” and 3) Level III “Detailed Analysis”.  The evaluations become more intensive, with additional measures required, at each level.

Standards and Certifications

Some energy audits are performed with the intention of attaining or improving a third-party rating or certification. There are several types of energy rating and certification programs at play in the commercial real estate industry, including:

ENERGY STAR: A federal program designed to encourage energy efficiency and reduced carbon footprint for commercial buildings, ENERGY STAR certification requires that a building meet strict energy performance standards set by the EPA. Specifically, a building must earn an ENERGY STAR score of 75 or higher, indicating that it performs better than at least 75 percent of similar buildings nationwide. An energy assessment designed for ENERGY STAR certification can identify EEMs that will allow the property to improve energy consumption until the 75 percent mark is reached.

LEED:  LEED (Leadership in Energy and Environmental Design) is a “green” rating system used all over the world to measure energy efficiency and environmental sustainability. There are LEED standards for new construction as well as LEED for Existing Buildings (LEED-EB), which offers operations and maintenance standards for reducing energy consumption. An engineer who is LEED-accredited can perform an energy audit designed to address LEED standards.

GRESB: The Global Real Estate Sustainability Benchmark (GRESB) is an annual assessment of the sustainability of a portfolio of real estate. It is designed to provide transparency to real estate investors regarding energy efficiency, environmental and social impact, and sustainable governance. Portfolio owners must complete an annual survey—25% of which is based on individual energy consumption. Therefore, an energy audit of each building in the portfolio may help the portfolio manager identify opportunities to improve GRESB rating.


Across the country, more and more localities are requiring commercial building owners to benchmark their energy use data, which measures how a building rates against similar buildings within its class, and then disclose their energy rating. Benchmarking allows owners, investors and lenders to compare a building’s energy performance to that of other buildings, as well as to monitor changes to energy performance within a property or portfolio of properties.

Putting Energy Audit Data to Use

All of the data gathered about a commercial building is useless without a plan for how to use it. A proper energy audit will determine and outline which EEMs will help the building owner reach target energy reduction goals and offer the best return on investment. The EEMs section of the energy audit will specifically detail how the recommended EEMs might be implemented, and what the costs and payback would be.