The Generalized Subtraction Correction Algorithm for Measuring Duct Leakage Using a Blower Door

The Generalized Subtraction Correction Algorithm (GSCA) improves upon the Modified Subtraction method for determining duct-leakage-to-outside using only a blower door. GSCA utilizes attic pressure both to calculate a generalized Subtraction Correction Factor and to properly identify and assign the correct pressure-difference between the ducts and attic responsible for the calculated ductleakage flow. This paper also describes the normal procedures that enhance the accuracy of data collection and the subsequent tests on the resulting information for validating the applicability of GSCA to an individual home. GSCA collects associated pressure-coupling data and enhances the reliability of house-leakiness results.