There are many ultra-sonic devices being marketed to consumers that claim to repel bats. People often call to ask if purchasing one of these devices will solve their bat problem? If only these worked, it would be an effective way to solve the problem. Unfortuantely, we have not found that these devices repel bats. Bats do use echolocation - a type of sonar - to find food. However, these devices do not seem to repel bats from a home.
This photo is of a bat that tucked itself inside an electrical outlet that was missing the cover. The outlet was used to power an ultrasonic device.