An energy audit is a comprehensive evaluation and analysis of a building’s current energy use.
Results from energy audits provide insight for building owners and also identify the most economical and energy-saving opportunities. Audits alone do not decrease energy usage; energy-saving strategies must actually be applied in order to see results. However, the implementation of these cost-effective opportunities can result in a payback period typically ranging from six months to four years, depending on the savings approaches utilized.
Any existing building is a candidate for an energy audit, but especially those that consume excessive energy, are considering building upgrades, or have never before been audited.
Energy Audit Process
The energy auditing process can be separated into two main steps, shown below:
- Walk-Through Analysis: Energy Auditor Inspection and Interview
The auditor will perform multiple tests throughout the building, take measurements, interview building owners and occupants, and locate energy-saving opportunities. In total, this process usually takes between two to four hours to complete.
- Energy Survey and Analysis: Report and Implementation
Following the initial appointment, the auditor will provide a full description of problematic energy areas and then offer recommendations for energy systems partially based off of occupant tendencies.
Building owners should research financial incentives related to their proposed building improvements. For a summary of regional, statewide, and national financial incentives, please refer to GBA’s Green Building Incentives packet.[CM1]
Auditing Tests and Techniques
A professional auditor uses a variety of techniques and equipment to determine the energy efficiency of a structure. A few of the most popular tests are:
- Blower Door Test: Measures a building’s airtightness, or the amount of air leaks and hot spots in the building envelope.
- Infrared Scan or Thermographic Inspection: Special cameras and videos measure and display surface temperatures, which reveal problematic areas of air infiltration and missing insulation.
- Duct Blaster/Air Distribution System Test: Locates leaks within ducts that could cause inefficiencies during forced air heating and cooling. Duct leakage in homes typically wastes 20% to 40% of heating and/or cooling energy.
- Heating System Inspection: Checks and tests efficiency of systems to reduce energy costs and improve safety and performance.
- House Ventilation Inspection: Checks indoor and outdoor air exchanges.
- PFT Air Infiltration Measurement Technique: Similar to a blower door test, this records air leaks and hot spots in buildings over time. Unlike the blower door test, however, the PFT (perfluorocarbon tracer gas) technique takes into account atmospheric pressure, weather, wind velocity, and any other activities that would affect air infiltration rates.
- Thorough Examination of Past Utility Bills
- Lighting Assessment
- Room-by-Room Examination
Benefits of an Energy Audit
- Energy Savings: Acknowledging and updating energy inefficiencies automatically reduces a building’s demand for energy. An energy audit also increases the building owner’s knowledge of operating systems and their proper maintenance, which subsequently further decreases energy usage.
- Financial Savings: Energy savings and financial savings go hand-in-hand. By identifying and committing to strategies that help reduce energy consumption, a building’s energy costs can be greatly reduced.
- Sound Investment: Even though energy audits require an initial fee, attending to hidden energy problems can prevent owners from facing future costs and repairs. Also, a building’s resale value is increased when energy efficiency techniques are adopted, as buyers prefer high-efficiency homes and buildings. According to a study by The Appraisal Institute, for every $1 decrease in annual energy costs, the market value of a home increases by $20.
- Increased Occupant Comfort: Indoor environmental quality and overall occupant comfort levels can be raised by simply managing select systems in a building. For example, by upgrading an HVAC system, air flow can be regulated by providing heating and cooling only when necessary. Improved lighting levels can also create a more comfortable atmosphere while reducing energy costs.
Thinking of Doing an Energy Audit
If you are looking to have an energy audit done on your building, make sure that your chosen energy auditor does thermographic inspections, or contacts other companies to do one. Thermographic inspections allow one to see where the heat is in their space, and where the heat is escaping. This information can be pivotal to the outcome of your audit.
Below is a list of preparations that building owners should undertake prior to an energy audit:
- Make a list of energy-related problems that exist within the building.
- Do not burn wood in a fireplace 48 hours prior to testing.
- Clean ashes from the fireplace and close the flue damper.
- Close and lock all windows and doors for building envelope testing.
- Collect 12 to 24 months of gas and electric utility bills.
- Building Performance Institute
- Residential Energy Services Network (RESNET)
- Association of Energy Engineers (AEE)- Certifications