We bought this originally for my mom, to be able to manage and see the comings and goings of caregivers. When she passed, we put the lock on our own front door. The door faces the west and is protected by a storm door.  But the sun must be too much for it because the batteries keep going and now there is corrosion on the top battery contacts. I tried cleaning them off but the unit won't work at all now. Very disappointed because we lived being able to give codes to friends and family.