They will overwinter here, depending on the location of the nest. They are trying to get the nest deep enough into the building to find enough heat/protection to keep them alive all winter. Most nests fail to do that, but I've seen them chew through just about any material necessary to get in. I always blast the nests with spray in the early evening or early morning, when most of them have landed. They will keep coming back to the same place. I don't think the spray has much residual effect at all.