Mezuza in a balcony

A balcony having 3 sides enclosed by a fence or a wall, and on its fourth side is an entrance to the apartment (which is the only way to the balcony) must have a Mezuza (Shulchan-Aruch Yore-de'a siman 286 seif 7).

There is discussion among the Poskim ,on which side of the door , the Mezuza should be placed:

(1) If the balcony is more than 4 cubits (=91in.) by 4 cubits, some poskim say it should be on the right side of the exit from the room to the balcony (Ta"z siman 289 se'if katan 4, Shu"t Minchat Eliezer vol. II siman 40, Shu"t Minchat Yitzhak vol. I siman 8).
But other Poskim claim it must be put on the right side of the entrance from the balcony to the room (Shu"t Beit Meir, and Chazon-Ish Yore-de'a siman 168).

(2) If the balcony is less than 4 cubits by 4 cubits ,the Mezuza should be on the right side of the entrance from the balcony to the room, according to all the opinions.
In any event (on whichever side of the door the mezuza is affixed and independent of the balcony's size) the Mezuza should preferably be affixed without a Bracha (=blessing)!!!

(3) The Chazon-Ish says that if the balcony has another entrance to the street , the Mezuza would be affixed with Bracha!

(4) For further details concerning a balcony, look in Sefer "Pitchei-Shearim" pg. 328,329.