This program explores design methods to improve thermal performance in window, curtain wall, and door systems by reducing heat and cold transfer through the glazing system. Studies have proven the health benefits from increased exposure to natural light through expanded use of daylight and views. Careful consideration must be taken when connecting the protected interior environment with the exterior environment to minimize heat loss and meet energy optimization goals. Understanding, recognizing, and using the thermal barrier options in aluminum fenestration systems allows architects not only to realize the benefits of properly leveraging the technologies available but also to maximize the connection between the interior and exterior environments.