The traditional idea of a "barrier" that keeps the warmth in and the cold out isn't new. In a home the most common barrier is insulation. In windows and doors it's called a "Thermal Break" and just like insulation it stops heat from escaping or cold from entering your home. Developed in Europe, our Thermal Break is positioned to the outside of the joinery which means the cold does not have the chance to get near the warmth inside. Therefor it performs much better as a "barrier" which results in advanced thermal performance. Here are some examples.