Energy Audits: The Steps and Content

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An energy audit, an assessment of the energy needs and efficiency of a building or group of buildings, can be informative for an affordable multifamily rental housing development as well as provide a roadmap for the most cost-effective improvements to make.

But what are the steps in an energy audit? What is done? How much do they cost? And how long does the process take?

David Jackson, a senior associate with On-Site Insight (http://www.on-site-insight.com), provided the answers to these questions in a recent interview. The Boston-based company performs energy audits, conventional and green capital needs assessments, and other services.       According to Jackson, there are three different levels of energy audits, each with a different price tag. The simplest, or Level 1, is typically for homes or small apartment buildings and generally involves a quick walk-through of the property and perhaps a survey form that the owner fills out. These can range from the free energy audits that utilities provide up to $1,000 or $1,500. Level 2, priced from $1,500 or $2,000 up to $3,500 or so, will usually involve gathering information on such things as utility usage and the specific equipment at the building, but probably not provide an assessment of existing conditions nor utilize complex modeling software.

At the top, from $4,000 in cost on up, is Level 3, an “investment grade” energy audit that Jackson noted can take about 15 business days to complete from initial client contact to delivery of the final report. Jackson described the steps in the Level 3 audit that On-Site Insight conducts of multifamily rental housing properties. The term energy audit is actually a misnomer because it also assesses water usage and air quality in addition to energy usage. “It’s probably more of a utility assessment and a utility audit,” Jackson says.

The Steps in an Audit

  • Step 1. The auditor determines which utilities that the owner pays for and seeks to collect utility bills for the last 12 months showing actual usage and costs, for fossil fuel (e.g., natural gas, fuel oil), electricity, and water and sewer. Also collected, from drawings and plans, interviews with the owner or manager, and other sources, is basic information about the property itself, such as its location, the number of buildings, type of construction, brand and type of windows, the current HVAC and boiler system, etc.
  • Step 2. The auditor, or several people for large properties, then makes a site visit, which typically takes one to two days. The team walks through and examines the building, the exterior of the building and property, and a sample of the occupied and vacant apartment units (or all buildings and a sample of units in each, for multiple-building projects). The team identifies and assesses the condition of the building envelope and its elements (e.g., wall systems, windows, doors, caulking, insulation); of mechanical systems and equipment (e.g., boilers, HVAC, hot water tanks); and of lighting systems. It runs tests on components, equipment, and appliances to determine their exact energy or water usage and efficiency. Within apartments, it measures energy usage and water flow/temperature, such as for showers. The team also measures indoor space conditions (temperature, humidity, and carbon monoxide and carbon dioxide levels). As part of the site visit, the team takes photographs, including infrared photos that can show temperature differences within wall systems, in piping, at a steam trap, or other places. This reveals areas of building heat loss (in winter) or gain (in summer), as well as indicate whether certain equipment is failing.
  • Step 3. Back at the office, the auditor plugs the information and data gathered from Steps 1 and 2 into a sophisticated computer software program (On-Site Insight uses TREAT, Targeted Retrofit Energy Analysis Tool, developed by PSD Consulting) to build an “energy model” of the property. This shows what the property’s actual current usage levels should be for the different kinds of energy utilities (water usage modeling is done by hand). After making sure that the model is accurate, the auditor then reviews the 10 to 15 different possible areas for improvement measures (e.g., lighting, motors, boilers, controls, building envelope, appliances) to determine where the biggest gains can be made. Then, one at a time, the audit plugs different specific improvement into the model, in a “what if” scenario, to pinpoint which are the best from a cost-benefit standpoint. The metrics that On-Site Insight applies to determine whether a specific feature or benefit is cost-effective include the savings-to-investment (SIR) ratio, the payback period, life cycle costs, and net present value. Depending on the location, the software can also be used to assess, for example, whether it makes sense to switch to a different available energy source for certain equipment or uses at a property (e.g., electric to natural gas).
  • Step 4. The auditor prepares and sends to the client a written preliminary report, which contains a narrative describing the building’s current utility usage, current conditions (e.g. equipment), plus recommended measures to reduce energy and water usage. The narrative is augmented by photographs and by spreadsheets showing such things as actual field readings and the results of life cycle cost analysis.
  • Step 5. The auditor has a discussion with the client about the preliminary report and answers questions. The client, for instance, might say it has just $200,000 to budget for improvements and asks the auditor to identify the top “big ticket” improvements from all of the recommended measures that would fit within this budget. Jackson points out that some recommended measures are “interactive”; these measures complement each other, they are meant to be done together and not alone.
  • Step 6. The auditor revises the written report to focus just on the measures selected by the client, which the client can then use as a roadmap for making the improvements. The report also lists, ranked in order of cost-effectiveness, additional other measures that could be done later, budget permitting.