wasps, hornets in attic
It would be a good idea to identify what type of wasp/hornet you are dealing with. Go to our website and view photos. http://extension.umd.edu/hgic/insects/stinging-and-biting
Normally if the nest is located outdoors, with the first hard frost the queen will overwinter elsewhere and the workers will die. The nest is not reused the following year. Since the insects are indoors, take some time to investigate and then take steps for control.
You may need to hire a pest control company to do this as these insects can be mean where their nest is involved and proper protection is needed. The insects can also do interior damage. You also have the option of hiring a bee keeper that controls yellow jacket and hornet nests. See the attached link http://www.mdbeekeepers.org/swarms.html