What Happens During A Residential Energy Audit

Posted on January 3rd, 2011 by

You have decided to have an energy audit performed to determine the cause of your home’s energy related problems.  You have researched companies, checked references and agreed upon a price. The day of the energy audit has arrived.  Now what?  Depending on your level of determination and willingness to spend money, you are likely to have one of the following audits performed (least to most comprehensive):  clipboard audit, sales audit, and whole home assessment.

Clipboard AuditThe clipboard audit was your choice if the person at your front door is armed with nothing more than a clipboard, pen, and flashlight.  These audits are typically offered, free of charge, by utility companies and outreach organizations.  The audit takes less than an hour and involves a walk-through of the home and a quick peek in the attic and perhaps the crawlspace.  The information is not detailed, not quantitative, and only identifies the most obvious issues.  As the saying goes….You get what you pay for.

Sales Audit As consumer awareness of “being green” rises, companies are using low-cost or free audits as a sales tool for the product they sell (i.e. windows).  This does not mean that all companies offer biased audits.  However, if they focus on selling a specific product, then it increases the chances proper attention is not being given to other areas of the home. “Sales audits” take 2 hours or less and are usually performed by a technician using a blower door.  Often, the audit is followed with an on-site report accompanied by a glossy presentation promising to save an overly optimistic percentage of energy.  Addressing only one aspect of your home’s problems can be, at best, ineffective and, at worst, dangerous to the home’s occupants.

Whole Home Assessment - These audits are performed by 3rd party auditors certified by BPI and/or RESNET.  When the auditor arrives, you might be surprised by the amount of equipment they carry.  The typical inventory of equipment, at a minimum, includes a blower door, ductwork testing equipment, an infrared camera, a ladder, and instruments such as carbon monoxide and combustible gas detection monitors.  This type of whole home approach takes 4 – 6 hours depending on the size and complexity of the home.  The audit starts with an interview to determine your concerns and is followed by a walk-through.  First and foremost, audits are intended to address your concerns.  Therefore, be ready to describe the exact issues and questions you want addressed.  It may be a drafty room, questions about construction quality, or why your utility bill is so high.

Exact measurements of your home are taken, including detailed descriptions of the construction.  The auditor spends a great deal of time visually inspecting every accessible inch of the home, including crawlspace and attic areas.  Before diagnostic testing is performed, several steps must be taken.  Water heater(s) and furnace(s) are turned off and/or set to pilot, fireplace ashes are covered, interior doors are opened, and exterior windows and doors are closed.  You can assist in the process by completing these items beforehand and ensuring all HVAC registers are accessible.  Now, the blower door test can be performed. The main component is a fabric covered frame and fan temporarily inserted into an exterior door frame.  The fan creates negative pressure within the home, allowing the auditor to measure and identify (via the infrared camera) air infiltration into the home.

HVAC ductwork testing is typically performed with a duct blaster, which is essentially a smaller version of the blower door.  The auditor seals the HVAC registers with clear film and measures the leakage of the system via pressurization of the ducts.

Finally, this audit requires verification of the safe operation of gas appliances.  Referred to as Combustion Appliance Zone (CAZ) testing, it is composed of measurements in and around gas furnaces, water heaters, ovens, or other gas-burning appliances.  As part of the test, all gas supply lines are checked for leaks.

At the end, the auditor should walk through the home with you and explain the highlights of the audit.  While some auditors may present a summary report at this point, all should prepare a detailed report with photos of identified defects within a few business days.  The report should provide solid quantitative information and serve as the benchmark for the home’s performance.  Improvement recommendations are grouped by order of importance and serve as the guide to implementing improvements.  Upon making payment, be sure to receive all needed paperwork, such as an invoice, to facilitate any rebate or tax credit for which you may be eligible.

Written by James Thomas, Green Summit Consulting

James Thomas is a BPI Certified Building Analyst, ICC Energy Inspector and Plans Examiner, and the Vice President  of Green Summit Consulting.

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