Repeatability of whole-building airtightness testing in a residential wood-framed building under varying weather conditions

This study investigates the repeatability of whole-building airtightness testing under varying weather conditions in a two-story, wood-framed residential building with an enclosure volume of 818 m 3 and an area of 532 m 2 , located in Victoria, Canada, situated in Climatic Zone 4C (Marine), characterized by mild, wet winters and cool summers. Air leakage tests, performed in accordance with ASTM E779, were conducted using blower door pressurization and depressurization methods. Weather variables recorded during testing included wind speed (2–14 km/h), indoor (17–23 °C), and outdoor (5–16 °C) temperatures, and relative humidity (indoor: 34%–59%; outdoor: 46%–96%). Regression analysis revealed no significant correlation between weather variability and airtightness metrics. Depressurization tests consistently demonstrated more airtight results compared to pressurization. These findings reinforce that blower door testing results are repeatable and reliable despite weather fluctuations, validating the applicability of single-event airtightness tests for evaluating building envelopes.