A balance assembly for a sliding sash window, where a spring-loaded pulley arrangement is interconnected between the window frame and the window, to counter the weight of the window, and permit ease of opening and closing the window. The spring-loaded pulley arrangement is located within a housing, which also facilitates attachment of the shoe. The shoe of this balance assembly being rotatable between a first and a second position to permit fitting the assembly into the side of the window frame, when the shoe is in the first position, and to permit final installation of the assembly when the shoe in the second position. The shoe is retained in the first and second positions by detents. This rotatable shoe feature permitting installation, of the Balance Assembly of this invention, into a window frame at later stages of the window assembly sequence.