Q: I have a problem with excessive dust use good filters replace regularly blower clean evaporator coil. Where is the dust coming from?

Infiltration is a source of dust. Also, the filter system is designed to reduce re-circulated material through the cooling system and ductwork. A filter’s job is to keep the equipment and ductwork clean. A lot of indoor/outdoor activity can allow dust into the home. Other causes of infiltration are: doors not properly sealed, attic access not properly sealed and canned lighting. If the material is fibrous and light in color it is most likely coming from carpets or cloth flooring (rugs). Also, the dryer being inside the house, linens and dry cleaning can also contribute. Ductwork infiltration is grainy and dark, unless you have white blown in insulation. Material coming from inside the house will be more fibrous and lighter in color. Sealing face plates and wall plugs can also help reduce infiltration.