Why Are There So Many Spiders in My House

Why Spiders Come Inside

Spiders move indoors because houses offer three things they need: shelter from weather and predators, a steady supply of small insects to eat, and places to mate and lay egg sacs. A home with other pests, clutter, or gaps around doors and windows becomes an easy target, and once one spider finds entry, others can follow the same pheromone trails or simply exploit the same openings.

What Attracts Spiders to a Home

• Prey insects: Flies, mosquitoes, moths, and ants give spiders a reliable food source, often concentrated around windows, lights, and damp areas.
• Shelter and warmth: As temperatures drop in autumn and winter, spiders seek stable indoor temperatures, especially in garages, basements, and corners.
• Moisture: Cellars, bathrooms, and kitchens with leaks or condensation attract both spiders and the insects they hunt.
• Clutter: Cardboard boxes, stored clothing, and stacked items provide dark, undisturbed hiding spots for webs and egg sacs.
• Exterior lighting: Bright lights near doors draw flying insects, which in turn draw hunting spiders inside.

Common House-Invading Species

Most indoor spiders are harmless house spiders such as the common house spider (Parasteatoda tepidariorum) and the daddy longlegs, also known as the cellar spider. Occasionally, species like the yellow sac spider or wolf spider wander indoors. While most are nuisance pests, a few can bite if handled or pressed against skin, and correct identification helps you decide whether a professional inspection is worthwhile.

How to Reduce Spiders Indoors

• Seal cracks around windows, doors, pipes, and foundation vents with caulk or weatherstripping.
• Reduce outdoor lighting near entry points, or switch to yellow sodium bulbs that attract fewer insects.
• Remove clutter from garages, closets, and basements where spiders can hide and build webs.
• Vacuum corners, ceiling edges, and under furniture regularly to remove spiders, webs, and egg sacs before they hatch.
• Address other pest problems and fix moisture issues to cut off the food and water supply that keeps spiders returning.

When to Call a Professional

If you notice large numbers of spiders, repeated egg sacs, or a sudden spike in other insect activity, a pest management professional can identify entry points, treat harborages, and help you break the cycle. A single service can give you a baseline, but long-term reduction depends on sanitation and exclusion work you maintain between visits.