If a bat is flying around inside your home, the fastest way to get it out is to open a window or exterior door, turn off all indoor lights, and close the doors to other rooms. Bats navigate by echolocation and are naturally drawn toward open air. In a dark room with one clear exit, most bats will find their way out within minutes. If the bat has landed and is resting on a wall or curtain, you can place a small container over it, slide a piece of cardboard underneath, and carry it outside.
Scaring a bat by chasing it, swinging at it, or making loud noises usually backfires. A panicked bat flies erratically and is harder to guide out. The goal isn’t to frighten the bat so much as to give it a clear, calm path to leave.
Getting a Bat Out of Your Living Space
The U.S. Fish & Wildlife Service recommends a simple sequence: confine the bat to one room by closing interior doors, then open any window or exterior door in that room. Turn off the lights. Bats avoid well-lit spaces and will orient toward the darkness and airflow coming from outside. Stand back and give it space. Most bats will circle the room a few times and then fly out on their own.
If the bat has landed somewhere and isn’t moving, it may be resting or exhausted. Wear thick leather gloves (never handle a bat with bare hands), place a plastic container or small box over the bat, and gently slide stiff cardboard between the bat and the surface. Take it outside and release it near a tree or elevated surface so it can take off. Bats can’t easily launch from flat ground.
Deterring Bats From Porches and Overhangs
Bats that roost under eaves, porches, or carport ceilings are a different problem than a single bat trapped indoors. For these outdoor roosting spots, a few low-tech deterrents can make the area less appealing. Mylar balloons, strips of aluminum foil, or ribbons hung from the ceiling and allowed to move in the breeze disrupt the still, sheltered conditions bats prefer. Nontoxic aerosol pet repellents (the kind sold for dogs or cats) can also discourage bats from returning to a specific spot.
Bright lights near roosting areas help too. Bats strongly prefer darkness, and a well-lit porch or overhang becomes far less attractive to them. Motion-activated lights or a simple floodlight left on at dusk can push them to find a quieter roost elsewhere.
Why Ultrasonic Devices Aren’t Reliable
Ultrasonic repellers marketed for bats sound appealing, but the science behind them is weak. A study testing broadband ultrasound broadcasts at wind turbines found reductions in bat activity ranging anywhere from 2% to 64%, with results varying wildly between years and conditions. The researchers concluded the technology was not ready for broad use. One major limitation is that ultrasound fades rapidly over distance, especially in humid air, which means a small plug-in device in your attic covers very little space. You’re better off spending that money on physical exclusion.
Removing a Colony With One-Way Exclusion
If bats have taken up residence in your attic, walls, or chimney, the most effective long-term solution is a one-way exclusion device. These are tubes, cones, or mesh funnels installed over the entry points bats use to get in and out. Bats can crawl or fly out through the device but can’t get back in. Over a few nights, the colony leaves on its own.
Before installing exclusion devices, you need to identify every gap bats are using. Bats can squeeze through openings as small as a half inch. Watch the exterior of your home at dusk and note where bats emerge. Seal all secondary gaps with caulk or mesh first, then install one-way devices at the primary entry points. After a week or so with no bat activity, remove the devices and seal those final openings.
Timing matters. If you’re doing this during warm months, you need to check whether you’re dealing with a maternity colony. Female bats gather in groups during summer to give birth and raise pups that can’t yet fly. In many states, installing exclusion devices during this period is either illegal or strongly restricted. In California, for example, the protected window runs from May 15 through September 1. Other states set similar windows, often June through mid-September. Sealing bats out during maternity season traps flightless pups inside, where they die. The best time for exclusion work is early spring (before pups are born) or early fall (after pups can fly).
If you plan to evict a colony, consider putting up a bat house nearby before you start. Bats that lose their roost need somewhere to go, and a bat house gives them an alternative that keeps them in the area eating insects rather than searching for another crack in your siding.
What Not to Do
Mothballs are one of the most common DIY bat repellents people try, and they’re both ineffective and potentially illegal. Mothballs contain naphthalene, which the EPA has linked to nasal cancer and other serious health problems. Using mothballs as a pesticide in attics or wall voids is a violation of federal pesticide law because they are not registered for that purpose. The fumes in an enclosed attic can also seep into living spaces, creating a health risk for your family.
Killing or harming bats can carry serious legal consequences. Several bat species are protected under the Endangered Species Act, and violations can result in fines up to $50,000 and up to a year in prison. Even common bat species receive varying levels of state protection. Beyond legality, bats are enormously beneficial. A single bat can eat thousands of insects per night, including mosquitoes and agricultural pests. The goal should always be removal, not extermination.
Cleaning Up After Bats Leave
Once bats are gone, you’ll likely need to deal with droppings (guano) they left behind. Bat guano can harbor a fungus that causes histoplasmosis, a lung infection you get from breathing in spores. The CDC recommends never sweeping or shoveling dry guano, because that sends spores airborne. Instead, spray the material with water (adding a small amount of dish soap helps reduce dust further) until it’s thoroughly damp, then collect it in sealed bags for disposal. An industrial vacuum with a HEPA filter is another option.
For small amounts of guano in a well-ventilated area, a dust mask rated N95 and gloves may be sufficient. Larger accumulations, especially in enclosed attics, are best handled by a professional cleanup service. There are no EPA-approved disinfectants specifically effective against the histoplasmosis fungus, so physical removal of the contaminated material is the primary strategy.