Bats are very choosy when selecting roosts, preferring warm spaces, away from draughts so they are protected from the weather. Ideally, several boxes should be hung up together facing in different directions to allow for changing conditions. On a tree, this could mean sitting boxes around the trunk, whereas a single bat box on a building may only be used for part of the year.
The boxes should be as high as possible in sheltered and sunny locations, ideally at least 4 meters from the ground. Putting boxes near fixed locations, such as hedges or tree lines may help the bats to locate them. It may take time for your bats to find their new house but if you are patient, you will soon see them swooping in and out.