The bat house will get best results if it is located 15 to 20 feet off the ground , facing the southeast. Bats tend to find bat houses mounted on poles much faster than those mounted on trees. You can also mount a bat house under the eaves of your house, provided it is high enough off the ground. Thin inside chamber and predator guard prevent squirrels and or other predators from entering. Inside fiberglass screen netting makes it easier for bats to hang on when they get inside.
Larger size makes it easier for bats to find.
This design from the Organization for Bat Conservation has a tested 80 percent occupancy rate. Extra long landing makes for an easier entry and exit for bats Front ventilation slat designed to keep bats from overheating. Landing perch below roosting chambers that make it easy for bats to land before entering. Constructed with wood screws instead of toxic or smelly glues. No paint or finishes are used.