Tell pests to buzz off with this guide to cluster flies and house flies
Cluster flies hibernate indoors during fall and winter, gathering near windows and in attics, while house flies stay active year-round near food sources.
House flies spread diseases by landing on garbage and feces, but cluster flies feed on nectar and don't pose health risks to your family.
You can prevent cluster fly infestations by sealing cracks around windows and doors before summer ends and temperatures start dropping at night.
Hiring a local exterminating professional provides reliable guidance when you need help with large infestations or want to prevent future problems effectively.
Flies are a nuisance no matter the season. Cluster flies and house flies might look alike, but their impact on your home are different. Cluster flies tend to sneak indoors during colder months in large numbers, house flies thrive year-round and spread germs. Knowing how to tell these types of flies apart can help you manage infestations effectively and keep your living spaces healthier.
| Type of Difference | Cluster Flies | House Flies |
|---|---|---|
| Size | About ⅓ inch long | ⅛ to ¼ inch long |
| Color | Brown-black body, silvery checkered pattern, reddish-brown eyes, golden hairs | Gray-black body, 4 dark stripes on back, bright red eyes, fine dark hairs |
| Activity | Gathers indoors in fall/winter to hibernate in attics, walls, or around windows | Active year-round and found near food and water sources |
| Behavior | Slow, sluggish, easier to catch or vacuum | Fast, agile, difficult to swat |
| Lifespan | 1–3 months, up to 2 years if overwintering | 15–30 days |
| Feeding | Plant sap and nectar | Decaying matter, food, and pet feed |
| Disease Risk | Does not transmit disease | Known carriers of many diseases from garbage and feces |
| Prevention | Seal cracks and gaps, screen windows/vents, insulate attic, treat exteriors before cold nights | Keep food sealed, clean spills, empty trash regularly, use tight lids |
| Treatment | Swat, vacuum, or use light traps; avoid indoor insecticides | Sticky traps, flypaper, or insecticides at breeding sites |
Cluster flies and house flies have key differences that set them apart, especially in their appearance.
House flies are small insects, usually measuring between ⅛ to ¼ inch in length. Cluster flies are larger, reaching about ⅓ inch long.
House flies have bright red eyes, a gray-black body marked with four dark stripes across the back, and fine dark hairs. On the other hand, cluster flies feature a brown-black body with a silvery checkered pattern, reddish-brown eyes, and noticeable golden hairs.
Cluster flies look for warm, sheltered areas where they can hibernate once the temperature drops. For that reason, they’re mostly seen during the fall and winter seasons. You’ll often find cluster flies attracted to and grouped in empty rooms, near windows, or hidden in attics and wall cavities.
In contrast, house flies appear anywhere they can reach food and water, such as kitchens and bathrooms. While they can cause problems all year long, they’re especially active in the warmer months and thrive in places with plenty of food.
House flies stay busy during the day and rest at night, zipping around with quick, darting movements that make them nearly impossible to swat.
Cluster flies couldn’t be more different—when the weather turns cold, they hole up in attics, wall voids, or around window frames to hibernate, and their slow, sluggish movements make them much easier to catch or vacuum up.
Houseflies don’t stick around for long, usually living only 15 to 30 days, depending on factors like temperature and food accessibility. The problem is, even in that short time, female houseflies can lay hundreds of eggs, which makes an infestation feel like it’s multiplying overnight.
Cluster flies, on the other hand, play the long game. Most only live a month or two, but if they find the right cozy spot to hibernate through winter, they can hang around for up to two years.
House flies aren’t picky eaters. They’ll eat anything from decaying organic matter to your leftovers to pet food—and then contaminate it with their spit or droppings.
Cluster flies are completely different. They’re not interested in your kitchen at all and stick to feeding on plant sap and nectar instead.
Cluster flies aren’t considered a health risk because they don’t transmit diseases, cause structural damage, or reproduce inside your house. They don’t lay their eggs on food or waste, but instead use earthworm burrows outdoors.
House flies, however, are well-known for carrying diseases since they spend their time landing on and feeding from garbage and feces. They are more dangerous to have in your living space since they can spread large amounts of harmful diseases. Even if they seem like a small annoyance, they need to be dealt with quickly to protect your family’s health.
If you want to keep cluster flies away, the best time to act is in the summer before they start looking for a place to hibernate. Seal any cracks, crevices, or gaps around windows, doors, siding, or even the roof. Make sure your windows and vents have snug screens, and check your attic for any insulation gaps. You can also treat exterior cracks and crevices with a residual insecticide before nighttime temperatures drop to help block them out.
House flies need a different approach since they’re drawn to food, garbage, and anything decaying. Keeping your home clean is key—wipe up spills, clear away food scraps, and don’t let garbage pile up. Store food in sealed, airtight containers so flies can’t get to it. Be sure your trash bins have tight-fitting lids and empty them on a regular basis.
When cluster flies get inside, there are a few simple ways to deal with them. You can swat them the old-fashioned way or grab the vacuum and suck them up off walls and windows. Insect light traps also work well for collecting them. Don’t spray insecticides indoors—dead flies left behind can attract other pests like beetles or even rodents.
House fly treatment calls for a different strategy. Sticky traps or flypaper near hot spots can help cut down their numbers, and fly-specific insecticides are another option when treating breeding sites or places where they’re most active. If either problem gets out of hand, it’s best to call in an exterminator in your area for guidance.
A reliable team for moves across state. My switch to a new place needed careful lifting through tight hallways. The movers checked the doorway first, then carried heavier pieces with slow, controlled movements. Their patience helped prevent damage, and I?d choose them again.
This company does it right. Firstly, I want to say that Landan was a joy to work with. He was so kind, transparent, and had everything under control. His entire team showed up ready to work and they were all very respectful of the fact that we were in an office space. A little backstory – we...
Krumlauf FloorsI had FabClean 614 clean my apartment, and she did an outstanding job. She was so professional and efficient. My apartment looks absolutely spotless every surface, every corner, all cleaned to perfection. Definitely highly recommend FabClean 614 if you're looking for top-notch cleaning...
Fab Clean 614Raven and crew does absolutely fantastic job. They are very professional if any concerns were to occur with any of her work she always took responsibility and finished out with a great job. I have worked with her business for a year and have always been satisfied. Very trusted business and...
Creations of Transformation LLCI would recommend this company to anyone! He showed up on time, was friendly, completed a very difficult repair on our dryer vent cover, was responsive, and pricing was extremely fair and competitive. I would have him back to do any of our repairs or cleanings without hesitation!
U.S.A. Dryer Vent, LLCBest cleaning I've had at my property
Ace Fireplace Services' chimney sweep service is truly exceptional. They used advanced technology to ensure a thorough cleaning process, and my chimney has never looked better. I highly recommend their services.
Ace Fireplace ServicesThis company went above and beyond with their work, chimney sweeps are usually pretty messy, but the clean up was spot on.!! Josh explained every thing that he was doing, and the things that he was checking to make sure the chimney was safe for me and my family. He was very professional,...
Supreme brick & chimneyGood workers and they do a good job.
Mira ConstructionMary Cleaning Service is amazing! The entire staff is very professional and they pay a great deal of attention to detail. I would definitely recommend!
From average costs to expert advice, get all the answers you need to get your job done.
Growing a veggie garden is hard work, but pollinators can make the load lighter for you. Learn the benefits of common pollinators in your vegetable garden.
What’s the difference between a deer mouse versus a house mouse? Get expert tips to identify and manage each kind of rodent.
How long do fruit flies live? The answer depends on factors such as temperature and food sources. Find out the average fruit fly lifespan.
Flies can seem like a never-ending annoyance, but there are ways to repel them. Find out how to keep flies away from your home and outdoor space.
Drain flies vs. fruit flies: what’s the difference? Compare these common pests and discover the best ways to prevent and remove them.
These pesky insects live in the film inside your pipes, but you can kick them to the curb. This guide will show you how to get rid of drain flies fast.
