It would appear that one of  your satellite carpenter ant nests has fallen victim to either a previous treatment or social disease. This commonly happens and is one of the reasons carpenter ants will have a main nest surrounded by 2-4 satellites. This way a component nest can die and the community will survive and resurrect itself through the effort of it's surviving satellites.

I'm not sure what you've been applying but based on what you're finding, it's obvious you need to do more. For starters I suggest you get some PHANTOM AEROSOL and treat as much of the area around the furnace as possible. I also suggest you start using some PHANTOM EC outside. As explained on it's product page, this unique active will slowly "kick in" and when it does, all the ants that have come in contact with it will die. This is very different from how many concentrates work and in fact, why most fail as a general way to control carpenter ants. Our article covers many options but based on your situation, I believe the Phantom is the way to go for now. Because of it's mode of action, any ants that forage over it will die and in you situation, this will surely happen. Ultimately you'll stand a much better chance at winning the war against this pest.

Here are direct links to the information and products listed above:

Phantom Aerosol:  http://www.bugspraycart.com/insecticide/aerosol/pt-phantom-17-5oz

Phantom Concentrate:  http://www.bugspraycart.com/insecticide/liquid/phantom-21-oz

Carpenter Ant Control:  http://www.carpenterants.com/carpenter-ant-control

If you have damage you should be seeing ants. And if you're seeing ants, trailing them to the nest would be easy and suggested. In all cases like this the first thing you need to do is dust with DRIONE. You'll see this listed in our CARPENTER ANT CONTROL ARTICLE. It will provide quick control since it penetrates all spaces and voids effectively. I suggest you watch the video as this demonstrates why it's so effective to use for spaces.

I also recommend spraying the foundation with some TERMIDOR to make sure you have a barrier in place that will get any stragglers or other nests you may have missed.

Here are direct links to the information and products listed above:

Drione:  http://www.bugspraycart.com/insecticide/dust/drione-dust

Carpenter Ant Control:  http://www.carpenterants.com/carpenter-ant-control

Termidor:  http://www.bugspraycart.com/insecticide/liquid/termidor-sc-20-oz

In most cases people are not aware of where the ants are nesting. In your case, you seem pretty sure where they're living. In fact bathroom walls are one of the most common locations for carpenter ants to use. These areas are usually moist and at least humid which carpenter ants love. No doubt this is why they target the bath room in so many homes.

I recommend using the most direct approach possible. That means drilling some holes and pumping the DRIONE dust into the wall void. Drill between the studs all the way around the room. These holes can be above any water proof walls you might have. And don't forget you can access this space from two sides. That means if there is a closet on the other side it might be easier to drill through that wall instead of the closet.

I also suggest doing a good dusting on the outside of the home. This should be done now and then in the spring I'd followup with some CARPENTER ANT BAIT and spray on the foundation. The BIFEN is a good product to use and if done throughout the year, you won't have any chance of a reinfestation.

Here are direct links to the information and products listed above:

Drione:  http://www.bugspray.com/catalog/products/page91.html

Carpenter Ant Bait:  http://www.bugspray.com/catalog/products/page253.html

Bifen:  http://www.bugspray.com/item/bifen_it.html

I wished you had read our article before you treated. When you know where these ants are centered, the only dust that should be used on them is something like PYGANIC. It's fast acting and won't allow them to relocate like it sounds like might be happening now. Boric acid is a stomach poison and won't do a good job on this ant unless they ingest it so for now, I expect you'll be seeing ants for some time. Your dusting most likely disturbed them but it doesn't sound like it was enough of a direct hit to knock them out. If you are lucky, enough of the dust will have made it's way to the heart of the original nest and may at least cause them to suffer severe losses. This could lead to their ultimate demise. If not, they will at least attempt to relocate and if they have enough supplies and members left in their colony, they could very well establish a new nest. Only time will tell.

For now, the only thing I'd suggest to do is set out some CARPENTER ANT GEL. Foraging ants will need food so make small placements in any room where you see activity. Chances are high some will accept the offering. Once they feed and return to the old or new nest (if either exists), the ant which fed will in time contaminate other members of the colony and eventually kill it. Other than the bait, there really isn't anything you can do. (And don't kill any ants you see; if you place out the bait the more ants foraging the faster the nest will be shut down…)

The CARPENTER ANT GEL wouldn't be the best option for this kind of problem. It doesn't do well outside since it's vulnerable to both the heat of summer as well as non-target insects. Honey dew based baits don't do well in extreme heat and they tend to attract many types of insects.  Additionally, there is most likely several ant nests involved here so you need something that will handle multiple nests without you having to know where any of them reside.

For this type of problem, clearly the TERMIDOR listed in our CARPENTER ANT ARTICLE is best suited. I have used it successfully on several trees around my property and in each case it did the job nicely. Because of it's slow action, you will be able to affect all the nests which have ants active on the surfaces you treat – even ant species other than carpenter ants. I recommend treating the tree trunk, tree limbs and as much of the tree house that is practical to treat. I might also consider treating around your house if this tree is in close proximity of it or any other important structure since carpenter ants typically forage great distances. Failure to have a good protective barrier in place will allow them to set up shop elsewhere if other active areas are ignored.

As explained in our CARPENTER ANT CONTROL article, these ants do nothing but forage around all day looking for food and working on their nests. I suggest you read the article which will provide a lot of insight to this ant as well as some practical things you can do to minimize this activity. I do suspect there is a nest either on the home or close by based on how much activity you said you see. But I have seen where they could be this active and still be living off the property.

As you'll learn in our article, there is usually a few things needed to control most infestations. And in most cases, knowing where their nest is located can be a big help in getting a quick resolution to the problem. That being said, your activity can best be controlled by baiting and spraying. Apply some MAXFORCE GRANULES to the yard which should cut down on the foraging. Next, spray the foundation with the TERMIDOR CONCENTRATE. This will provide much needed protection in case they are currently accessing the home in some location you cannot see. The way Termidor works, you'll be able to effectively control any nest on or in the home whether you know where it exists or not. Lastly, if you start seeing any inside the home, use the PHANTOM AEROSOL. It works like the Termidor and can solve problems even when you don't know where the nest is located.

Here are direct links to the information and products listed above:

Carpenter Ant Control:  http://www.carpenterants.com/carpenter-ant-control

Maxforce Granules:  http://www.bugspraycart.com/bait/granule/maxforce-gran

Termidor:  http://www.bugspraycart.com/insecticide/liquid/termidor-sc-20-oz

Phantom:  http://www.bugspraycart.com/insecticide/aerosol/pt-phantom-17-5oz

Carpenter ants are unique in that they will actually spend time removing dead ants from their colony. It could be you are finding dead ants that have been removed from a local nest. The key for you will be determining where the nest is located. It sounds like you are unsure at this time and as our Carpenter Ant article explains, many times it is hard to discover these locations. Remember, ants don't want you to know where they live. But unless you are able to either spray or bait where they are active, it's not likely you'll be able to resolve this problem any time soon.

That being said, I'm pretty sure there is a nest either in or on your home. I would be surprised if they are located far away; it's most likely they are very close based on the numbers you report. I'm thinking in the ceiling void, maybe behind some crown molding or in some air vents, since you're finding these ants out in the open. This is usually a sign of ants being "pushed" out of some small hole up high. Since homes can have nests which don't have ants visually seen all the time, this scenario is fairly common and happens all the time.

At this point the Carpenter Ant Gel might be your best option but you do need to locate the placement to where you have seen activity. From your message, I don't think you know of any activity so this might be hard for you to do. Remember, carpenter ants are nocturnal by nature so they could be out and about in the dark thus avoiding being seen. I suggest you place some of the Ant Gel where you're seeing the dead ones for starters. You are also welcome to give our office a call at 1.800.877.7290. One of our technical reps might be able to ascertain a better remedy after being able to discuss the matter on the phone.

Base don the fact that you've seen them each year for several years, I'm pretty sure there is either a nest in or on your house. Since carpenter ants can cause a lot of damage, it would be wise to attempt to do something before the situation gets worse. The first thing you should do is try to locate where the nest is. We have a great video in our Carpenter Ants in House article which highlights how you can find the nest.

Additionally, you should place out some Carpenter Ant Gel when they get active. Since most ants coming out of winter hibernation are seeking food, this gel will  be found quickly and should kill off some of the developing nests even though you won't know where they are located. This is one of the big advantages of the product and why it's both easy to use and effective.