Keeping bats out of a house requires sealing entry points and installing one-way exclusion devices, not sprays or ultrasonic repellents.
For the full breakdown, see our best Bat Repellent Spray guide.
When bats take up residence in an attic or wall void, most homeowners first reach for a spray, a fogger, or a loud ultrasonic gadget. Those products rarely solve the problem.
Doing it safely is a matter of timing. Excluding bats during the summer pup-rearing season can trap flightless babies inside the walls, where they die and create a worse problem. The process below follows public-health guidance and covers the tools, the timing rules, and when to call a professional.
Why Repellents Fail and Exclusion Works
Sprays, mothballs, ultrasonic devices, and chemical repellents do not reliably drive bats out of a house. Bats are stubborn once they have established a roost, and many repellent products simply mask the smell of the roost without changing the bats’ behavior. The permanent fix is denial of entry.
Exclusion works on a simple principle: bats leave every night to feed, so you give them a one-way door. Devices like exclusion tubes or netting let them fly out at dusk, but the angled flap or cone prevents them from crawling back in. After a few nights, every bat has left, and you permanently seal the final opening.
Finding Every Entry Point
Bats squeeze through gaps far smaller than people expect. The CDC advises checking for openings larger than a dime — roughly the width of a pencil — and sealing them with caulk, steel wool, or hardware cloth. Common entry points include:
- Cracks and crevices in walls, roofs, and floors
- Chimneys without caps, and unscreened vents
- Soffits, joists, and corner gaps
- Utility penetrations for pipes, wires, and cables
- Loose or warped exterior doors that don’t close tightly
Do a daylight inspection of the exterior, looking for dark stains around openings — bat guano and rub marks are telltale signs. Check the attic too, since bats can enter through one part of the roof and roost elsewhere.
The Step Order for Bat Exclusion
The order matters. If you seal every opening at once, you trap the bats inside. Follow this sequence:
- Inspect and seal everything except the active exits. Caulk cracks, fill gaps around pipes with steel wool or expandable foam, install chimney caps and vent screens, and repair loose doors. Leave only the openings the bats currently use.
- Install one-way exclusion devices over the active exits. These are tubes or netting cones that let bats fly out but not re-enter. Confirm which openings are active by watching the house at dusk and noting where bats emerge.
- Wait until all bats have left. Leave the devices in place for at least seven days — some guidance says 2–3 nights is enough, but a full week is the safer bet — and watch the exits each evening. When no bats emerge for several consecutive nights, you can assume they’re gone.
- Seal the final openings permanently. Remove the exclusion devices, then close the gaps with caulk, mesh hardware cloth, plywood, mortar, or metal flashing. Confirm no bats are still inside before sealing.
If you need to handle a bat that got indoors, the U.S. Fish and Wildlife Service recommends opening exterior doors and windows and turning off lights at night, then keeping children and pets away. For capture, use a sturdy container like a shoebox, protected hands in thick leather work gloves, or a tightly knit bag — avoid loose towels or loosely knit materials, because bat claws catch in them. Release the bat outdoors, high up and away from your body, and see qualified medical advice afterward, since CDC guidance stresses rabies prevention when any contact occurs.
Timing Rules and When to Call a Professional
Timing is the difference between a clean exclusion and a tragedy. State rules vary:
Some situations call for a licensed nuisance wildlife specialist. If bats are already inside living spaces, if you can’t locate all the entry points, or if the roost is large and long-established, professional help is the safe route.
Just know that the permanent fix is sealing the house, not spraying it.
FAQs
What is the fastest way to get a bat out of a single room?
Open exterior doors and windows, turn off interior lights, and leave the room. The bat will follow the darkness and the airflow to the open exit. Keep pets and children out, and do not chase or swat at the bat, which only drives it deeper into the house.
Is it safe to seal the house while bats are still inside?
No. Sealing every opening traps bats in the walls, where they die and decompose. Always leave at least one exit open, install one-way devices, and wait until you have confirmed no bats remain before permanently closing all gaps.
Can mothballs or ultrasonic devices repel bats permanently?
No. These products do not address the roost. Bats may be temporarily annoyed, but they return because the entry point remains open. The only permanent solution is exclusion: seal the gaps and deny entry.
References & Sources
- U.S. Centers for Disease Control and Prevention. “Bats: Rabies Prevention and Bat Exclusion.” Details entry-point sealing and September–April timing guidance.
- U.S. Fish and Wildlife Service. “Five Methods to Safely Remove a Bat from Your Home.” Covers capture methods and safe handling precautions.
