I have what I believe to be cluster flies all over the west wall of my house and getting into my house. How to get rid of them…fast!
You should caulk and screen all potential entry points, especially on the south or sunny side of your home. Control can be achieved by applying a pesticide to the exterior walls of the structure in an effort to discourage the insects from entering. This application should be made before any insects enter the structure, generally mid to late August depending upon the weather in any given year. One they have entered some professionals will fog an attic with an insecticide. The best way to identify and remove pests is by hiring a professional who can deal with the problem quickly and effectively. http://pestcontrolcanada.com/flies/cluster-flies