Bau.Tools BlowerDoor is an all-season testing procedure for detecting air leakages and backflows using BlowerDoor and thermography. Even the slightest temperature and pressure differences are sufficient to quickly and accurately locate leakages and backflows with Bau.Tools BlowerDoor, and then visualize them. Flaws that are hardly or not at all visible in a classic thermogram because of very minor temperature differences at differential pressure are calculated via sequential analysis and precisely visualized. Since the thermogram only shows the changes within the testing period, air leakages and backflows can be accurately distinguished from other problem areas. A new feature is the computer evaluation of all thermograms recorded during the testing period (Sequential Analysis), resulting in a clear and precise image.