by IowaNate » Mon Feb 02, 2009 10:56 pm
Terry and Dave gave great answers.
If bats wanted to live in your home, they would more then likely already be there. And while properly hanging a well-built bat house would very likely increase the numbers of bats in your area, your home should be secure if you have no gaps bigger than 1/2" x 1". Even then, the bats probably would've found that hole in your home long ago if your home was suitable for them.
If you end up getting a nursery colony in your bat house, you will probably find a great deal of bat activity during late Summer when the baby bats are learning to fly and exploring. As Terry noted, these young bats have the greatest probability of flying in an open window or open door...but the probablity is almost non-existant if you have screens on your windows and doors since bats do not chew or make holes of any kind.
Two of my bat houses are hung at a local Nature Center with 800 bats between the two, and they are mounted on the elevated deck of the building within 12 feet of doors and windows, and there has never been a bat that intentionally or accidentally found it's way inside the two story and 2000 square foot building in the 10+ years that the houses have been hung.
Happy bat housing!
Nate