Ensure that the screen door works in conjunction with the main exterior door. If the screen door is part of a two-part door with an exterior door, the screen door must swing out while the exterior door swings in. The hinges of both doors are on the same side of the doorframe.
Determine how much space is available on the surface immediately outside the door. This is especially important if the surface outside the screen door is on a raised landing. If the landing is not large enough to comfortably stand on and allow room for the door to swing to the outside, the screen door should swing to the inside. A screen door that swings in only works if there is no other door inside the screen door.
Mount the screen door opening out, if possible. This allows the door to be pushed open easily in the event of an emergency. It also reduces strain on the screen from pets and children pushing on the screen portion of the door as they try to get outside.