This Crystal® ThermoBlok™ fully welded vinyl replacement window is manufactured with exclusive chambered ThermoBlok™ designer extrusions. These ThermoBlok™ extrusions feature innovative insulating air barrier technology that reduce thermal transference from exterior of window frame to interiors, and “intercept” warm edge glass spacer technology for added thermal protection. These features reduce heating and cooling loads on HVAC systems, providing long term energy efficiency and utility savings to property owners. This series is offered as double hung, bay, bow, slider, casement, and coordinating architectural circle top shapes for enhancing curb appeal of home renovation projects. Features such as easy-to-clean, tilt out sashes, custom two-tone colors, and decorative grids make it popular with home owners.