Attic flies, which are also known as cluster flies, are insects that often migrate into homes in the fall, where they hibernate for the cooler fall and winter months. One of the best tips for getting rid of attic flies is to keep them from entering the house in the first place as trying to eliminate them after they are in hibernation can be difficult. Sealing cracks in the walls, roof, and windows is one of the best ways to get rid of these insects. Spraying the exterior of the house with insecticide can also be effective.
The most effective way to get rid of attic flies is to make sure that they stay outdoors. They enter houses through cracks in the roof or in the walls, cracks in door and window jambs, and open doors and windows. Cracks should be sealed at the end of the summer so that the insects have no way to enter the house. Tight-fitting screens should be placed in windows and doors.
It is also possible to place traps in attics or around windows to catch attic flies as they enter the house for the winter. Fly paper can be strung up around windows and doors to capture flies as they come inside. Bug electrocuters can be left in attics as long as they are not placed close enough to walls or insulation to cause a fire. Powdered eggshell or borax traps can also be used to either catch or kill flies as they walk across these surfaces.
Some insecticides are quite effective at killing attic flies. Before the flies move into a house for the winter, they can often be found along the exterior walls of the house, congregating on the warm walls as the air cools. Spraying the outside of the house with insecticide can kill any flies currently on the walls and prevent other flies from landing there.
It is possible to spray attic flies once they are inside, but it is difficult to do and can be quite messy. Bug bombs that release poison throughout a room can be used to kill the flies in an attic or crawlspace. Individual flies found around the house can be sprayed with household insecticides. Once the flies are dead, it is important to clean the area thoroughly so that other bugs, such as roaches do not move in to eat the dead flies.