The patent-pending, fusion-insulated AirCell™ frame fully insulates the window and eliminates the voids that lead to energy loss — paired with triple-pane glass and the metal-free Duralite™ warm-edge spacer, which cuts thermal conductivity by up to 45% and delivers the lowest U-value in its class.
Our EnergyCore line with triple-pane glass and argon gas is designated one of the Most Efficient ENERGY STAR® qualified products.