I was helping a friend move into her house from the apartment she'd been renting; as we picked up her couch from along the living room wall next to the air conditioner vent hundreds of wasps flow into the room. they had nested in an electrical line coming into the apartment and had eaten into the room to avoid the cold outdoors. when we picked up the couch, the opening into the apartment was exposed and they could come into the living room. we dropped the couch and ran. the building managers had to come at 10 pm to spray. check each of the rooms for some type of outdoor access, however small. good luck, it was creepy.