Steamers work by delivering lethal temperatures to where bed bugs may be hiding. Steam is very effective when bed bugs are on the surface of items and can be effective up to 3/4″ into fabric surfaces. In cracks and crevices, steam will kill bed bugs up to 2-3/8” into a gap. Use an infrared thermometer to monitor the surface temperature of the area being treated. To effectively kill bed bugs the surface temperature should be at least 160-180°F immediately after the steam brush has passed.