Why Is My House Full of Ants in Winter?

It’s easy to assume that ants are only an issue during the warm months, but the truth is, given the right circumstances, they can plague your household at any time of the year. Even in some of the coldest climates in the U.S., like the Northeast, ants can be an uninvited guest. This article explains how ants get in your house during winter, what they’re doing there, and how you can eliminate them. 

Do Ants Die in Winter?

No, it’s a common misconception that ants die as the seasons change. Instead, ants begin overwintering, a process of finding a safe place to stay warm during the winter months. They do this by tunneling deep underground, sealing the entrance to their nests, and huddling close to one another. 

Leading up to winter, ants will increase activity, foraging more intensely and building up fat for the colder months – this is why you often see more ants during September and October. As the cold weather begins to set in, their body temperature drops, and their metabolism slows, making them sluggish and slow, giving them the cue to begin hunkering down. Once winter rolls over and temperatures warm, ants will begin to move again. They open up their tunnels, continue foraging, and resume being a pain for most homeowners. 

Due to how ants deal with cold weather, you won’t likely see many running outside during winter. If you spot some scurrying about, it’s likely due to a jump in temperature, which can prematurely and temporarily wake ants up from their hibernation. However, finding ants inside your home during winter is another story, and it might signify much larger, more troubling problems.  

Why Are There Ants in My House in Winter?

If you spot ants in your home during winter, it likely means that an ant colony has taken up residence inside a portion of your home. Since homes are heated year-round, if ants have begun living inside, their body heat will never drop, removing the need for them to overwinter. As a result, if a colony is located within the structure of a home, it’s free to stay active all year.

Why Do Ants Come Indoors?

Ants come indoors in search of food, water, and shelter. Since homes can easily provide these things, your house can quickly become a colony’s favorite foraging spot. Ants are attracted to any source of food that is easily accessible, like crumbs, dirty dishes, spills, loose garbage, pet food, or piles of debris. Other household problems like leaks and severe moisture can also attract ants, so broken pipes, cracked or damaged window frames, or leaky sinks can bring them indoors. 

Depending on your environment, ants may be just as willing to create nests, or colonies, inside your home as they would outdoors. Ultimately, ants will choose to nest inside if your home provides easier access to food, water, and shelter than your yard, garden, or surrounding area. While indoor nesting is more common in the Southeastern portions of the U.S., it can technically happen anywhere the circumstances are right. 

Where Do Ants Nest Inside Homes? 

Ants like to nest where there are voids that they can construct their nest inside. Some of the most common places you can find indoor nesting colonies include:

• Inside walls 
• Within door or window frames 
• Inside or under foundation slabs 
• Under floors 
• Inside cabinets, shelves, or cupboards,
• Inside certain appliances and systems, like air conditioning systems 

What Kind of Ants Nest in Homes During Winter?

While just about any ant species can nest in homes, some are more likely to find their way indoors and set up shop. Some of the usual offenders for home-invading ants are the following: 

• Acrobat ants: Named for their tendency to raise their abdomen (rear end) when threatened, this species of ant is tiny, only one-eighth of an inch in length. They’ll nest inside windows and doorframes, siding, and trash piles. 
• Argentine ants: More common in the Southern portions of the U.S., these ants are originally from Argentina, Uruguay, and Brazil. They’re most likely found inside walls, insulation, and other warm places. 
• Carpenter ants: These ants act like termites but are much less damaging. These pests build their colonies inside moisture-damaged wood, and you can find them inside: 
  • Window and doorframes 
  • Siding 
  • Voids in walls 
  • Crawl spaces, attics, and basements
  • Hollow doors
  • Gutters and eaves
  • Wood portions of the home that contact the ground
• Little black ants: As their name implies, these ants are indeed tiny at one-sixteenth of an inch in length. They can squeeze into many household locations, like under carpets, inside walls, between brickwork, inside woodwork, and throughout appliances or systems. 
• Odorous house ants: These smelly invaders love moisture and will nest inside walls with broken or leaking pipes, under sinks, between foundation cracks, and in humid basements. 

How To Get Rid of Ants During Winter

It can be extremely difficult to move ants once they’re inside your home. Getting to the colony can be a nightmare if they’ve set up shop deep within your walls or under your foundation slab. Furthermore, insecticides or bait traps on indoor colonies aren’t advised, especially if you have pets or young children. But there are some steps you can take to get rid of ants in the wintertime, like removing food sources, making DIY traps, and contacting a commercial pest control company.

Step 1: Clean up Food and Trash

The first and most important part of ant removal and prevention is getting rid of their food source. Clean up all trash, food particles, and debris in infested areas. If you see any ant activity in the kitchen, you must dispose of dirty dishes, clean kitchen counters, and tidy up the pantry. It also doesn’t hurt to invest in airtight, sealable containers. 

Step 2: Create a Pet and Child-safe Ant Killer

While most commercial ant killers and insecticides aren’t pet and kid-safe, some handy DIY options exist. 

Diatomaceous Earth

Sprinkle a light dusting of food-grade diatomaceous earth along locations ants frequent. This natural substance made from fossilized kelp is lethal to insects but safe for pets, children, and adults. While this powder is great for killing ants on the spot, it’s usually a temporary solution and doesn’t typically kill a whole colony.   

Baking Soda and Sugar Bait

Mix equal parts baking soda and confectioner sugar, add to a small dish or paper plate, and place in locations where ants frequent, but that will be difficult for pets and children to access. While not strictly poisonous, baking soda can be dangerous to pets and children when ingested in large amounts. While this bait can kill a whole colony, you’ll have to be more careful with this if you have pets or small children. For extra protection, you can add this mixture to a water bottle, seal it with a cap, then poke one side with holes. Place the bottle horizontally with the holes facing up – the ants can access the toxic mixture through the holes, but pets and children will have a harder time getting inside. 

Step 3: Seal Entry Points

The final step in removing and preventing a winter ant infestation is finding the entry point they used to get inside and sealing it. Ants often find their way indoors through small cracks in the foundation, openings in siding, holes in window and door screens, gaps in window frames, and holes around utility lines. We recommend inspecting the outside of your home once per year, either in spring or fall, looking for these entry points and using a silicone-based caulk to fill these gaps. 

Final Wintertime Ant Control Tips

While finding ants inside your home during winter can be distressing and unsightly, very few ant species pose a threat to humans or structures. If you find ants indoors during the colder months, your best bet is to remove what’s bringing them inside, namely access to water and food sources. Clean areas infested with ants thoroughly, and try to find any sources of moisture and remedy them. If ants persist, you can try homemade ant killers or pet-safe bait traps. If all else fails or you see ants year-round, it’s best to contact an exterminator or pest control services to eliminate your ant problem. 

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