The best way to keep bats out of the house is to prevent them from re entering.
How to drive bats out of your attic.
They are designed to fit on top of any hole which bats have been using as an entryway.
Killing them is both inhumane and will create an unlivable environment due to the smell of a colony of decaying bats.
Bats need a silent and dark place to roost during the day and if you have a white noise machine active 24 7 this will prevent bats from roosting in your area.
You must follow these steps.
Bats have to have a.
Seal up 100 of the openings.
Use a vacuum first to suck up all of the loose droppings decomposing bat bodies and any other materials.
Determine the species of bat.
This is one of the more serious and complicated problems in the field of nuisance wildlife control.
Safely remove the entire colony.
A white noise machine for those who are unaware basically will create static noises similar to the sound of a static tv channel.
Bats will hibernate in the winter if the temperature stays at around 35 to 40 f.
Then remove any soiled or damaged insulation from the attic and or walls.
If not run an extension cord upstairs to your attic and turn on floodlights or work lights in an area away from flammable material.
Make sure there are no baby bats.
Find out how they are getting in out.
Or set up a battery run lantern or two.
Specifically work out how many of them there are and work out what time they will all have left for the evening.
Once your attic or home has become undesirable to bats it s time to exclude them from your property.
When all the bats have left focus on sealing all of the cracks and fissures they use to enter.
Afterward you will need to scrub the area with an enzyme based cleaner.
To properly remove the bat droppings and debris.
Ah bats in the attic.
How to remove bats from attic.