If she has had bats in her house more than once, I would guess they they are living in her attic, around her chimney, under the siding, etc. Or perhaps they are living in one of those places at her neighbor's.
She should go outside and watch for bats exiting her house, or look for stains or droppings around the outside of her house. The droppings look like mouse droppings but they are very lightweight because they are made of insect skeletons.
If she does have bats in her attic, she should put up a bat house, then do an exclusion following these guidelines:
http://www.batcon.org/index.php/bats-a- ... intro.htmlShe could of course learn to live with bats in her attic, many people do. They are providing her neighborhood with a tremendous bug-consuming service. But she should figure out how they are getting from her attic into the living space, and seal that up. Also she should have the guano removed every once in a while, to prevent it from weighing down and/or soaking through the attic floor - it is awesome fertilizer that sells for $6/pound -
http://www.planetnatural.com/site/bat-guano.html