The belief that your design ideas and preferences, not energy or structural limitations, should determine the look of your project is built into every Western Window Systems Performance Line product. Discover moving glass walls and windows that address energy and structural requirements while promoting thin profiles and large expanses of glass. Energy efficiency goals are easier to achieve, thanks to across-the-board low U-value ratings and low-E argon-filled dual-pane glass paired with proprietary Insulbar for thermal performance and strength. Not only is the line designed to withstand a variety of weather conditions, it also has a design pressure rating of 50 on sizes exceeding industry minimums.