No-see-ums can enter a home through small openings like windows, doors, and vents. However, they usually do not infest homes or live indoors because they require a moist environment to survive and breed. They are commonly found in outdoor areas like marshes, swamps, and near bodies of water. If you are experiencing bites inside your home, it is more likely to be from other pests like mosquitoes, fleas, or bed bugs.