Depending on the way's windows open, common types of windows are casement, double hung, awning, slider, bay bow, specialty, fixed windows. Casement window is one of popular window types in modern homes, so is fixed window. The following passages is going to introduce to you about energy efficient of casement window and fixed window.
CASEMENT & FIXED WINDOW
According to Wikipedia, Casement window is "a window that is attached to its frame by one or more hinges at the side. They are used singly or in pairs within a common frame, in which case they are hinged on the outside. Windows hinged at the top are referred to as awning windows, and ones hinged at the bottom are called hoppers".