Window replacement contractors need to understand four major aspects of code compliance for windows: energy conservation, safety glazing, fall protection, and emergency escape and rescue. For the first two aspects, requirements for replacement windows in existing buildings are the same as those for windows in new construction. That is, energy codes limit the U-factor and solar-heat-gain coefficient, and if the window is located in one of seven locations deemed “hazardous” by the IRC, then it must be safety glazed, typically using either tempered glass or security film. These both mainly affect the cost of the window itself.
