Artificial lights, strong odors, inadequate temperatures and high-frequency sounds are all potential bat deterrents. One of the best methods of evicting bats is to simply seal entrances and prevent the animals from returning to the roost.
Bats are incredibly beneficial animals that may save the United States over $3 billion in agriculture losses every year. However, bats roosting in human dwellings present a health risk. Various methods of bat exclusion and deterrent exist to humanely exclude bats from a structure. One proven way to exclude bats is to locate and seal entrances. This is done in a manner that allows bats to exit but not return. This type of exclusion is only possible when no dependent pups are present in a roost.
Since bats are nocturnal, bright, artificial lighting can discourage them from using a particular area. Bats are also very particular about roost temperature. Creating a drafty environment renders a space unsuitable. Strong odors and high-frequency sounds are other potential bat deterrents.
High-frequency sounds have questionable effects on bats. Sonic devices meant to work for rodent control have little effect on bats. Sonic devices at wind turbines have had moderate success in repelling bats and decreasing mortality, but the cost in relation to its actual effectiveness makes this method largely unusable.