We recommend baiting near the heating vent. We offer the Complete Ant Kit that contains everything you need to bait for ants, Advance 375A a protein based bait, Optigard Ant Bait Gel a carbohydrate based bait and 12 bait stations to keep the bait fresh and in place. The ants will eat the bait and carry it bait to the nest, eventually eliminating the colony. We do not recommend spraying insecticide into the heat vent.
We would recommend the Complete Ant Kit. It comes with two different food sources the ants will be attracted to. The Advance 375A is a granular protein bait. The Maxforce FC Ant Bait gel is a sugar bait. The kit also comes with bait stations that are refillable and can be be placed indoors and outdoors around your home.
If you are looking for a spray, we would recommend using Suspend SC. It is a general insecticide that can be used indoors as well as outdoors. The residual indoors is up to 90 days and 30 days outdoors. This will be sprayed along th baseboards and cracks and crevices indoors. This can also be sprayed in your attic as well.
Please let us know if you have any additional questions.
Its sounds as if you are treating for Grease Ants, which are also known as Thief Ants. Since Grease Ants (aka Thief Ants) usually have nests indoors and outdoors, we recommend doing a complete inspection to try and locate the nest. You will want to treat both the inside and outside of the home to fully treat for Grease Ants. Examples of outdoor nesting sites can be: under rocks, around walkways, in rotting wood and exposed soil. Treating the perimeter of the home with Termidor SC 1ft up and 1ft out from the structure is recommended since Termidor SC lasts for 6 months when used for ant control.
Indoors nesting sites can include under countertops, in wall and cabinet voids, and behind baseboards. Thief ants are also known for building nests very close to, if not inside the nests of other ants, from whom they steal their food. Protein or grease baits seem to be the most accepted by Greast Ants, but they will sometimes switch over to a sweet-feeding cycle for a time. We recommend using our Complete Ant Kit on the inside of the home to meet both nutritional needs of the ants.
Please read our How to control Thief Ants Article here: http://www.domyownpestcontrol.com/how-to-get-rid-of-thief-ants-a-277.html