They'll most likely be fine. Most likely only have another few weeks left.
Sounds like might be hard work to move them from an air vent.
I've had records from people who've had nests in porches, sheds, house walls, even a kitchen, with no problems.
If people get unhappy a compromise may be to re route the bees using a bit of board, drain pipe of similar. I've advised people to do this to get traffic away from eg. front doors. And it's worked. The bees are redirected to exit and enter a few feet away rather than right where the people are. If you do this, it needs to be done in dark and preferably on a Friday night so bees have a couple of days to learn their new nest entrance and settle down.