The brown marmorated stink bug (BMSB) hibernates during the winter. Stink bugs invade homes in the autumn looking for hibernations spots, such as window air conditioners. The BMSB produces a horrible odor when threatened, which makes them a nuisance in the home. To keep stink bugs out of air conditioners, the homeowner needs to initiate a multi-faceted prevention program. Stink bugs can enter homes through any small opening and not just through the air conditioner.
Place fiberglass shade-blocking screens on the outside glass of windows holding air conditioners. They may be sold as "solar shade window screens" but they will also block insects from coming through that part of the window, according to the South Carolina Energy Office.
Remove small air conditioners from windows at the end of August. Stink bugs enter the home through the air conditioner. Stink bugs can use the air conditioner itself as a hibernation place but may also move through the air conditioner into other areas of the home. If the air conditioner is too big to move, go to Step 3.
Place weather stripping around windows, doors and air conditioners that are too large to remove. Stripping seals off narrow cracks that stink bugs can crawl through.
Repair or cover any holes in window screens. To keep bugs out, the mesh diameter should be 20 or finer.
Fit the entire outside portion of a window air conditioner with a commercially made air conditioner cover. These covers may be sold as water-blocking covers. The air conditioner cannot be run with a cover on.