Air Leakage Analysis from Blower Door Test Data: ACH50 Calculation and Method Comparison

Project Description In building performance testing, ACH50 (Air Changes per Hour at 50 Pascals) is a key metric used to evaluate a home's airtightness. This value is typically derived from standardized blower door testing procedures and calculated using specialized software such as NRCAN’s  Hot2000 , which includes proprietary calibration curves for equipment like the  Retrotec 5000 fan (A-setting) . This project provides pre-collected blower door test data (including time-series pressure readings and a validated ACH50 value from Hot2000) and challenges students to  analyze the data independently  using Python. Students will apply a power-law regression to estimate airflow across various pressures, calculate ACH50 based on known house volume, and compare the accuracy of their result with the trusted benchmark. The project further invites students to compare the results obtained using: The full available pressure dataset (from OCR or supplied), A reduced set of 6–8 equidistant pressure points between 15–50 Pa. This real-world calibration exercise offers valuable insight into engineering accuracy, the role of instrumentation, and the importance of method selection.