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.

Automated OCR Pipeline for Extracting Pressure Readings from Blower Door Test Videos

Blower door tests are used in building diagnostics to measure airtightness by monitoring indoor pressure changes. These tests are often recorded on video, but manual data extraction from the video footage is time-consuming. In this project, students will develop a Python-based tool to automatically extract pressure readings from a video using screen capture and Optical Character Recognition (OCR). The script will capture one frame per second, isolate the region displaying the pressure value, apply OCR, and output the readings to a structured format such as CSV or JSON. This project will help students develop skills in real-world automation, computer vision, and data engineering—all within the context of sustainable building science.