Performance testing is a critical component of any HERS® Rating. The procedures for these tests are covered in detail by ANSI/RESNET/ICC 380-2022. This standard gives Raters and Rating Field Inspectors the required methods for setting up equipment, taking measurements, and reporting results. This work must be performed carefully and consistently to ensure accurate results and ratings. Chapter 4 of this standard covers the equipment, setup, and testing of the whole-house infiltration, commonly referred to as blower door testing. This technical bulletin will cover portions of Chapter 4. Every Rater, Rating Field Inspector, and Quality Assurance Designee should read the entire chapter and become familiar with the Standard’s provisions. Dwelling Unit and Equipment Set Up For whole-house infiltration testing, proper setup of the dwelling unit and equipment is crucial. All exterior windows and doors must be closed and latched, and all interior doors between rooms must be open. All air-moving fans, such as exhaust fans, air handlers, and dryers, are to be turned off. Vented combustion appliances should be turned off or placed into pilot mode. Additional requirements for preparing the dwelling unit for the infiltration test are provided in Section 4.2 of ANSI/RESNET/ICC 380-2022. The blower door fan must be installed in an exterior door or window with an unrestricted air pathway into the dwelling unit. The fan location must allow the equipment to move air freely, with no obstructions to airflow within 5 feet of the fan inlet or 2 feet of the fan outlet (4.3.1.1). These clearance requirements are important because nearby walls, furniture, equipment, or other barriers can affect airflow across the fan, potentially making the manometer reading unreliable. At this point in the test setup, the indoor temperature and outdoor temperatures are recorded (4.3.1.3). The elevation above sea level must also be recorded to within 500 feet (4.3.1.4). These values will be used after the test has been performed to correct the results for environmental conditions. Performing the Infiltration Test Once the equipment is set up correctly, the test must be run to produce a stable, representative result. The test result must be measured as an average value over a period of at least ten seconds (4.4.1.1 for single-point testing, 4.4.2.1 for multi-point testing). The most efficient way to accomplish this for a manual infiltration test is for the manometer to be set to a time-average setting that meets this requirement. For an automatic test program or app, no changes to the time average setting on the manometer are required, as the app already is set to take a 10 second average at each pressure station. This averaging period helps reduce the effect of wind, pressure fluctuations, and other short-term changes that could affect a single reading. For a single-point test, the tester will first check and record the baseline pressure across the dwelling unit enclosure (4.4.1.1). The tester will then unseal the fan and adjust it to create a 50 Pa pressure difference (with a margin of ±3 Pa). Once the correct pressure has been reached, manometer is set to an average of at least 10 seconds, and the result is recorded (4.4.1.2). For a multi-point test, the procedure is largely the same. The primary difference is that the tester will measure infiltration at multiple, approximately evenly spaced points, or pressure stations, at pressures between 10 Pa and 60 Pa. Each of these pressure stations will be measured as an average over at least a ten-second period (4.4.2.2). Applying the Results of the Infiltration Test Whole-house infiltration results require corrections before they can be used. The previously recorded indoor and outdoor temperatures, and recorded elevation must be used to correct the infiltration result for the environmental conditions. A correction spreadsheet is available on the RESNET® website under Resources to assist with this calculation. These corrections are necessary because air density changes with temperature and elevation, and those changes can affect the measured airflow. When a single-point test is performed, the result must also be adjusted using a 10 percent single-point adjustment factor after the correction for temperature and elevation has been made (4.5.1). This detailed testing procedure, outlined in Chapter 4 of ANSI/RESNET/ICC 380-2022, is designed to ensure the accuracy and repeatability of the whole-house infiltration test result. Producing accurate, repeatable test results helps us strengthen confidence in our Raters, Rating Field Inspectors, and the Network as a whole. Raters and Rating Field Inspectors should direct any questions about ANSI/RESNET/ICC 380 and whole-house infiltration testing to their RESNET Accredited Rating Provider. For additional assistance, please contact the RESNET team at technicalsupport@resnet.us.
