It is late summer in the Northeast, and many insects, pests, and wildlife turn their thoughts and energy toward preparing for winter. Cluster flies are one of the most notorious. Homeowners will begin to see them from this point on.
Why are they called cluster flies?
Often confused with the standard house fly, cluster flies are more substantial in size and nowhere near as quick. Often called attic flies, cluster flies, as the name implies, live in large groups in the warmth of your attic, crawl space, or storage closet. They do not reproduce but hibernate, lying in wait for the warmth of springtime to call them back to the outdoors.
Can cluster flies cause damage to my home?
Cluster flies are considered an annoyance, but not a danger to the structure of your home. Once inside your attic or crawlspace, these clusters of flies can hibernate in large numbers. Often found on the western facing or southern exposure sides of your attic, cluster flies are drawn to the warmth inside your home. If the attic or crawl space temperature begins to rise, the flies may start to migrate out, thinking it is spring.
- Cluster flies often release a sweetish odor when alarmed or killed.
- Dead cluster flies inside your home during the winter months function as a food source for rodents and other insects.
- These flies sometimes leave tiny dark-colored spots of excrement on walls or windows, but these spots are not known to carry any human disease-causing organisms.
How can I keep cluster flies from entering my home?
Homeowners should share the mindset of the cluster flies and prepare your home for the fall and winter months. The best way to prevent cluster flies is never to let them in your home! Our home maintenance agreement for pest control provides regular treatments between June and August. These treatments can prevent cluster flies from entering and infesting your home once the weather turns chilly.
We apply insecticides on the outside of the structure and inspect for any areas vulnerable to entry.
- Gutters- Cluster flies love to nest here!
- Window seams and frames
- Door frames/screens
- Soffits and eaves
- Vents on the roof
- Electrical outlets

Clean your house gutters! Cluster flies love to nest here!
Cluster flies are skillful at finding ways of getting inside your home and patiently lay dormant waiting for spring. Should the weather warm, they awake and look to get outside, forcing them out of hiding and into your living space. Therefore, you see the flies in your home in the dead of winter.
Application to the surrounding soil of your home could also assist in minimizing cluster fly infestations and entry during late fall/early winter.
How do I get rid of cluster flies?
Prevention is the key, and as discussed above, a maintenance plan with Accurate Pest Control ensures consistent treatment as well as regular inspection of your property by a trained professional technician. Preventative spraying now can help with reoccurrence.
Contact us in the Albany, Schenectady, or Saratoga, New York area for a free home estimate. Ask us for information on annual maintenance agreements and keep your home, or business, healthy and pest free!