The real energy-saving doors and windows, not a single use of partition bridge aluminum profiles or Low-E hollow glass energy-saving materials, it is a perfect combination of the system, the comprehensive results of each link performance, indispensable, to measure the energy conservation of building doors and windows should mainly consider three elements, namely, heat loss (heat exchange), heat convection and heat conduction and radiation; 1. Convection is the circulating flow of hot and cold ai......