Abstract: The present invention is an apparatus and method of assembling a block and tackle counter balance for windows that reduces the cost of manufacture and installation. In particular, the balance provides vertical support to a window sash using a semi-rigid channel, a top shoe for insertion into one end of the semi-rigid channel, and a bottom shoe for insertion into another end of the semi-rigid channel. Connected to the top shoe is a spring, and a block and tackle pulley assembly is connected between the bottom end of the spring and the bottom shoe, wherein a cord from the pulley assembly extends outward from the bottom shoe for connection to the window sash.