A laminated glazing unit is disclosed having controllable transparency to visible light and a solar load reduction element which preferentially excludes infrared radiation while being substantially transparent to visible light. The solar load reduction element comprises a Fabry-Perot interference filter which includes a film stack deposited on the laminated surface of the outer ply of the glazing unit. The film stack includes at least a zinc oxide film followed by a silver metal film followed by a second zinc oxide film followed by a second silver metal film followed by a dielectric film which provides good long term adhesion durability to an adjacent laminating layer of PVB or like material. The dielectric film preferably is zinc oxide with a thin overcoat of chromium oxide, SiO.sub.2 or, alternatively, is tantalum pentoxide. The electro-active means for controlling the transmission of visible light through the glazing unit comprises electrodes, separate from the SLR element, which are deposited on facing surfaces of inextensible polymeric material such as polyethylene terephthalate.