Abstract: A window assembly comprises, a first base member and a second base member, both being of general T-shaped configuration, and having a middle portion and two transversely extending arms. The arms have a longitudinal channel and a plurality of longitudinal slots therein. The middle portion of the second base member is slidably insertable in the longitudinal channel of the first base member. A window assembly further comprises first and second window panes being removably inserted in the longitudinal slots formed in the arms of the first and second base members. A plurality of seals are positioned in the slots and serve to sealingly support the first and second window panes in the respective sots. A seal is also positioned between the second base member middle support and the first base member longitudinal channel and is in sealing engagement therewith. A plurality of plastic blocks are positioned between the first and second base members and are in sliding engagement therewith.