Disclosed is a warm window system that utilizes individual buss bars that are placed within the space between an inside window pane and an outside window pane and creates sufficient physical force to create an electrical contact on the tin oxide layer on the inside surface of the inside pane of glass. An insulating nonconductive layer can also be used in conjunction with the buss bars. That include metal strips, braided wires, spring loaded indentations, etc. The buss bars have a modulus of elasticity to ensure sufficient electrical contact with the tin oxide layer. The buss bars can be used with either hard coat or soft coat tin oxide coatings on tempered glass or annealed glass. Electrical connections and wires are hidden from the viewing area of the warm window system to enhance the aesthetic value of the warm window system. Retrofit systems allow use of the warm window system in conjunction with an existing installed window system.