There are two common methods used for the detection of air leakage, these being smoke detection and thermal imaging.
Smoke detection is the process of using smoke as a sighting instrument to identify areas where air is escaping from a dwelling. It works on the principal of sealing the room you wish to test and pressurizing it; a smoke puffer, smoke stick etc. is then used. The smoke will travel to any area where there is an air leak because of the applied pressure in the room. This method only points out the point inside the dwelling that the smoke is escaping from; it does not show its path of travel once inside the wall or its escape point to the outside.
