Generally harmless to humans, Boxelder bugs are nuisance pests, as they gather in large numbers on the warm walls of a home or business.
When it begins to cool, boxelder bugs try to find shelter in cracks and crevices. This normally means window sills. Inevitably you’ll get the few that can find their way inside the home through these window gaps. You don’t want to squish boxelder bugs. They can leave a permanent orange stain.