I live in an apartment building. I am on a low floor. Five days ago my mom spotted a wasp on the dining room windowsill. I killed it. Then the next day we saw another one in the same spot, I killed that one as well.
This past Wednesday, July 29, 2015 the exterminator came. He sprayed, went outside and sprayed a lot inside the hole, and got rid of the nest and plugged up the hole.
Yesterday and today my mom and I saw a couple of more, not at the same time in the same spot, I killed those as well.
The Maintenance guy looked in the apartment and saw no wasps, however, he went downstairs and said there is another hole under our dining room window but in the brick.
However, we cannot do anything until Monday, August 3, 2015 when exterminator comes back and the building manager and his staff come back to work.
How can we tell if the wasps will be totally gone after exterminator does what he has to do on Monday.
Also we have central air conditioning. My mom and I also were wondering when the contractors came to clean the AC vents for the summer could they have punctured something and this gave the wasps access.
So far we are lucky because the wasps are only in the dining room (windowsill)
It is not uncommon for wasps to get inside in late summer and early fall, nests are at their maximum size and there's a lot of activity (see http://www.livingwithbugs.com/yellowjacket_wasps.html
for general information about yellowjacket wasps). The exterminator should be able to get rid of the nest without much trouble, especially if they know where it is. I doubt that the A/C maintenance has anything to do with the wasps getting inside unless you actually see them coming out of the inside vents.