How to Safely Exclude Bats From Your Home

🧰 What You'll Need

One-way exclusion devicesHardware clothCaulkFlashlightHeadlamp

📋 Steps

Confirm bat species and maternity season dates

Most US bat species have a maternity season when pups can't fly (typically May 15 - August 15). During this period, exclusion is illegal — you'd seal pups inside to die. Check your state's maternity dates and plan exclusion for September-October or November-April.

Conduct a dusk watch to find exit points

Sit outside at dusk and watch for bats emerging. Note every exit point. Bats emerge from very small gaps (1/4 inch for some species). You may see 5 exit points from one structure — all must be addressed.

Install one-way exclusion devices at primary exits

One-way bat tubes or netting flaps allow bats to exit but not re-enter. These are installed over exit points. Commercial bat exclusion tubes are available or make your own from screening.

Seal all secondary openings

While one-way devices are in place at primary exits, seal every other gap 1/4 inch or larger with hardware cloth and caulk. Bats will attempt to find alternative entry.

Wait 3-5 nights then seal primary exits

Allow all bats to exit over several nights. Confirm empty with flashlight inspection at dusk (no movement). Then permanently seal the primary exit points.

Install bat houses nearby

Installing bat houses (on posts, away from structures) provides bats alternative roost sites. This keeps beneficial bats in your local ecosystem while removing them from the structure.

💡 Pro Tips

Bats are federally protected under the Endangered Species Act and state laws — killing bats is illegal in all states
Professional bat exclusion companies are familiar with all state regulations and required timing
Guano accumulation may require professional bio-remediation if significant — dry guano from some bat species can harbor Histoplasma capsulatum

⚠️ Warnings

Never attempt exclusion during maternity season (typically May 15 - August 15 in most states) — pups will die inside and create an odor problem
Never use any pesticide on bats — this is federal and state illegal

💰 Cost to Fix This Problem

Approach	Typical Cost	Best For
DIY materials only	$25–$75	Mild or early-stage infestations
Professional service (one-time)	$150–$400	Active infestations or when DIY has already failed
Ongoing service contract	$400–$800/yr	Prevention and long-term peace of mind

Approach

Typical Cost

Best For

DIY materials only

$25–$75

Mild or early-stage infestations

Professional service (one-time)

$150–$400

Active infestations or when DIY has already failed

Ongoing service contract

$400–$800/yr

Prevention and long-term peace of mind

Costs vary by region, property size, and severity. Get at least two quotes before hiring.

✅ How to Know It's Working

Pest control success is measured in weeks, not days. Here's what to look for:

Week 1–2: You may see increased activity as pests are flushed from hiding. This is normal.

Week 2–4: Activity should drop noticeably. Bait traps or sticky monitors should show declining counts.

Week 4–6: New activity near zero. Any resurgence means a population was missed or re-introduction occurred.

💡 Monitoring tip: Place sticky traps in corners and along walls before you start treatment. Counting catches weekly gives you objective data on whether the population is declining.

👷 When to Call a Professional

DIY is appropriate for small, contained infestations caught early. Call a licensed professional when:

You've tried DIY twice with no lasting improvement

The infestation involves a wall void, crawlspace, or area you can't safely access

There's a health risk involved (hantavirus, anaphylaxis risk, etc.)

The problem covers more than one room or a large outdoor area

You have children, elderly, or immunocompromised individuals in the household

⚠️ Rule of thumb: If you've spent more on DIY materials than a professional visit would cost, it's time to call.

❓ Frequently Asked Questions

When is it legal to exclude bats?

Most states prohibit exclusion during maternity season (May through August) when flightless pups are present. The legal window is typically September through April. Check your state wildlife agency for specific dates.

How does one-way exclusion work?

Exclusion devices installed over exit points let bats leave at dusk but prevent re-entry. Leave devices for 7-14 days to ensure all bats depart, then permanently seal openings. All exit points must be identified for success.

Are bats in my attic dangerous?

Bat guano can harbor Histoplasma capsulatum fungus causing histoplasmosis when inhaled. Bats are also a rabies vector, though individual bat rabies rates are low (less than 1%). Never handle bats with bare hands.

Do I need to clean up bat guano?

Small dry accumulations in unused attic areas can be left undisturbed. Large accumulations require professional cleanup with respiratory protection due to histoplasmosis risk. Contaminated insulation typically needs replacement.