By Tony Carrick | Updated Oct 1, 2021 1:05 PM

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Although many ant varieties can cause problems in a home, few are as potentially damaging as the carpenter ant. This aptly named species builds its nest by tearing tunnels through wood. If left unchecked, this can wreak havoc on a home—resulting in thousands of dollars in damage. The worst part? Once you have ’em, they’re almost impossible to get rid of. This is why it’s crucial to find a suitable solution that will eliminate the colony for good.

Carpenter ant killers offer a cost-effective alternative to hiring a professional exterminator to rid your home of destructive ants. These products come in various forms: sprays that kill on contact, liquid baits that attract and infect worker ants, which carry the poison back to their colony, and granules applied outdoors to prevent ants from getting inside the home.

This buyer’s guide contains shopping considerations and recommendations for effective products, to help find the best carpenter ant killer for your pest problem.

Understanding how the different types of ant killers work is key to addressing the carpenter ant problem your home is facing. Ahead, learn more about granules, sprays, and gels, as well as other factors to consider when selecting the right product.

Like many ant killers, formulas specific to carpenter ants come in two basic types: baits and kill-on-contact insecticides. True to its name, this type of insecticide kills ants within seconds of touching them. Kill-on-contact pesticides typically come in aerosol spray bottles.

Not only do these sprays kill the ants almost immediately, but many leave a residue that will kill other ants that scurry through the substance days later. While kill-on-contact products eliminate the immediate threat, they aren’t effective at destroying the colony unless sprayed directly onto an anthill.

Baits consist of a small receptacle that holds either dry pellets or a sticky liquid. The bait attracts ants and functions in one of two ways: either the pellets are collected and carried back to the colony, or a sticky liquid or gel sticks to the ants’ bodies. The ants carry the poison back to the colony, where it infects other ants and, with luck, the queen.

Bait toxin works on a delayed timeline, killing the ants days or weeks after exposure. This delayed action allows time for the ants to return and infect the entire colony. Although baits don’t offer the instant gratification of sprays, they have better long-term results by eliminating entire colonies.

Ant killers use a variety of active ingredients in the chemical war on ants. Borax is a particularly popular pesticide; the substance is deadly to ants but presents a low level of toxicity to humans, making it suitable for indoor ant baits. Hydramethylnon is another common active ingredient that’s lethal to ants while posing minimal risk to humans. Other active ingredients used in ant killer include indoxacarb, avermectin, lambda-cyhalothrin, and fipronil.

The Environmental Protection Agency (EPA) classifies these chemicals as “reduced-risk” pesticides, meaning they have low toxicity to humans. Keep in mind that a low toxicity level doesn’t deem these products as completely harmless; pesticides of any kind should be handled with care.

Ant baits come in several forms, each with a different application method and specific means of killing ants. Consider whether you prefer ant killer bait stations, granules, sprays, or dust based on the following characteristics:

Many of the active ingredients in ant killers pose no serious health risks to humans. However, consumers should still be careful when using pesticides in or around the home. When using an ant killer, it’s essential to take precautions to limit and prevent exposure. Keep the following tips in mind for application:

Carpenter ant killers are effective at more than eliminating and controlling ant infestations. These multifunctional products can also take out a broad range of other common pests, including roaches, fleas, crickets, termites, and other insects. Most manufacturers list the types of insects the pesticide treats on the product container.

Many ant baits have additional features that make them suitable for use in different environments. Ant killers with syringe applicators facilitate targeted applications, in areas like the small cracks and gaps between baseboard molding that ants can infiltrate. This allows the user to treat the affected area without overspray, minimizing exposure to humans and pets.

Bait stakes have a time-release poison that will not only take out existing colonies, but prevent ants from arriving and establishing new ones. Outdoor bait stations have waterproof housing to prevent rain from coming into contact with the poison, thereby ruining the bait station.

The list below features ant killers capable of killing ants that make their way into a home, while also able to take down an entire ant colony in a matter of days. These powerful ant killers come from some of the best-known producers of residential pest control products.

Terro’s popular gel-filled bait stations are an affordable and safe option for carpenter ant control. The concept of these traps is simple yet effective: The worker ants enter the trap, become covered in toxic liquid, then return to the colony to infect the queen—eliminating the entire population and ending the pest war. The baits are designed to destroy the colony in a few days.

The active ingredient is borax, so this bait is safe for use inside the home. Installation is easy: snap off the tab to open the entrance and place the bait station wherever there’s ant traffic. Terro’s ant killer comes in packs of six and 12.

While ant baits may not offer the instant gratification of killing compared to fast-acting sprays, baits are one of the most effective means for eliminating ants—and Hot Shot’s MaxAttrax is one of the best. These baits consist of a small ant house that attracts worker ants who enter, become covered in poison, then return to the colony to infect and kill the queen.

This bait’s active ingredient is indoxacarb, which is lethal to insects but listed as a “reduced-risk” pesticide by the EPA (meaning it poses low toxicity to humans). This ingredient is thus suitable for use indoors in places where ants are active. One of the advantages of this bait is its working time of up to 6 months, eliminating existing colonies while preventing the establishment of new nests.

This value pack includes eight ant baits at a bargain price, offering an economical solution to a carpenter ant problem. These ant baits feature a double-control bait, which includes two types of food to attract ants. The active ingredient, avermectin, works on a delayed time and kills infected ants within a day or two of contact. This gives the ant time to return to the colony to infect the rest of the population.

These baits effectively kill an entire colony within a week and keep working for up to 3 months, helping prevent the establishment of new ant colonies. These baits are suitable for indoor use in kitchens, bathrooms, and other living areas.

The syringe design of this Combat gel bait allows for a precise attack on ants. It works by injecting a line of gel in hard-to-reach places where ants travel or enter the home, such as small cracks around windows and along the baseboards. Ants eat the gel and then return to the nest where they deliver the poison to other ants before dying—destroying the colony in 3 to 5 days.

This bait gel contains the active ingredient fipronil, which kills ants just a few hours after ingestion. The syringe dispenses a thin bead of gel, suitable for areas where a spray might damage paint or the finish on furniture. It also minimizes the amount of poison distributed, reducing the toxin’s chances of coming into contact with pets and humans.

These granules kill on contact and come in a 3-pound bag, providing enough product for heavy infestations. The toxic granules are distributed by opening the bag’s bottom and shaking it, minimizing the need to mix or handle the pesticide. This application process makes for a safer and more convenient application style.

The granules contain lambda-cyhalothrin and dissolve into the ground. This product is designed for outdoor use on the lawn and around the home’s foundation, creating a barrier that prevents ants from entering the house. Any ants that touch it will die on contact. In addition to killing ants, it’s also effective against a broad range of other insect pests, including roaches, fleas, and crickets.

Ant sprays are effective at controlling an ant population and offer the satisfaction of killing the tiny intruders on contact. Many sprays, however, are harmful to pets and children. Raid uses essential oils that are toxic to ants but safe for humans and animals, providing a formula ideal for indoor use. Instead of pesticide ingredients, this spray uses lemongrass extract and geraniol, an extract taken from pine trees.

This versatile spray takes out more than ants. It kills roaches and 20 other common household insects. Use this spray around door casings, baseboards, and other crevices where ants infiltrate the home. This spray can stain certain finishes and paints, so be sure to test the product before using it.

Why wait for the ants to infiltrate the sanctity of the home before addressing the problem? Make a preemptive strike with this granule-based product from Amdro. This hydramethylnon pesticide is designed to be sprinkled around the entire home, creating a protective barrier that blocks ants from reaching the house.

Worker ants take the bait and return to the colony with it, poisoning the entire population and putting an end to the threat. The granules come in a large 24-ounce bottle with a shaker top that allows the user to sprinkle it around the home. A single bottle can cover up to 1,080 linear feet and lasts up to 3 months.

Most liquid ant baits are not suitable for outdoor use because they’re permeable to rain. Thanks to its innovative design, this liquid ant bait from Terro is impervious to rain. The bait is covered and elevated off the ground, preventing rain from getting in.

The ants come and go via a ramp. Stakes keep the bait firmly rooted to the ground, preventing it from tipping over. Once inside, the ants contact the poison, which uses borax as its active ingredient. The ants then return to the colony to infect others, and eventually, the entire colony.

While much depends on the size and location of the carpenter ant infestation, the TERRO T300B Liquid Ant Killer, 12 Bait Stations is one of the best options for most types of indoor use at home. For those who are looking for a product that is fast-acting and can target small areas indoors and outdoors, consider a product like the Combat Indoor and Outdoor Ant Killing Gel.

These recommendations for the best carpenter ant killers include a variety of types of products that can meet the needs of typical home users both indoors and outdoors. We narrowed our research to focus on products designed to tackle home infestations and considered products that are both fast-acting and work for a long time after installation to maintain a carpenter-ant-free home. Some of the products that made the list can kill on contact, attract and infect worker ants who carry the poison back to their colony, or are applied generously outdoors to prevent ants from getting inside a home.

While evaluating the products, we found that our favorites use active ingredients that are safe around pets and children, have easy application methods, and can be used on other pests. Some of the best carpenter ant killers that made the list have additional features like syringe applicators, time-release poison, and waterproof housings for outdoor use.

If you still have questions about carpenter ant killers, read on for answers to some of the most commonly asked questions on these insects and products.

Once they’ve established a nest in damp wood, carpenter ants will not move away on their own. The nest will continue to grow and expand unless it’s treated, which can result in serious damage to the home and other structures.

There are several options for treating a carpenter ant infestation. Granules for outdoor use are an excellent way of eliminating colonies in the yard or creating a barrier around the house. Liquid baits designed for indoor use are a good way to eliminate colonies by infecting worker ants who deliver the poison back to the nest.

While many ant baits will kill carpenter ants and other types, be sure to check exactly which species the product targets before making a purchase.

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