When hanging French doors be sure to check the doors' swing because some swing in and some swing out. Think about how much sunlight will come through the doors, and move furniture and decor that may fade in sunlight. Always fit exterior French doors with weather stripping.
Before installing exterior French doors, always take into consideration the size of the opening. Make sure the doors will fit in the opening, and understand that newer homes will generally accommodate a standard-sized French door. Older homes tend to have non-standard door openings, so make accommodations for that, if necessary.
Security is an important concern that should be addressed before installing exterior French doors. Make sure the doors have a three-point locking system to lock the door to the head jamb and the sill and lock one door to another. Most other door types offer better security than French doors, so if security is an issue, French doors may not be the appropriate choice.
French doors also provide minimal privacy and are more expensive than other door types. They are harder to keep clean because they are made of glass, but they are lightweight and help add more natural light to a room, increasing the sense of space.