All kinds of critters come into the house looking for a place to rest for the winter. Common nuisance pests are boxelder bugs, houseflies, squash bugs and the multicolored Asian ladybeetles. As you encounter nuisance insects, just vacuum them up. Avoid smashing them as some leave stains or odors when smashed. Don't store firewood in the house.
Insects can come in with firewood.
Leave the wood outside until you are ready to build a fire. Firewood should never be treated with insecticides and insecticides are often not needed for most home invaders.