The best, expert approved, bat houses are made from wood, which mimic soem bats' natural environment: rough tree bark.
But bats aren't the only animals that like wood surfaces...
Occasionally, woodpeckers might be tempted to bother your bat house. Let's talk about some ways we can prevent them from doing so.
How to Deter Woodpeckers
Avoid using any kind of noise deterrence, as that could also bother the bats. Woodpeckers can be deterred with pinwheels, shiny helium balloons, strips of aluminum foil, or reflective tape. Simply install these on and near your bat house, and these will help keep woodpeckers away from the bat house without disturbing the bats.
If your bat house already has a hole in it from a woodpecker, you should plug the hole with wood putty to discourage further activity. After that, your bat house will function fine and the bats will be able to sleep safe and sound.