When you’re researching replacement windows for your home, there are many factors to consider and choices to make. Windows are designed to open in different ways, including double hung windows that open from the top or bottom, as well as slider, casement, awning, hopper, bay, and bow windows. Windows come in a variety of colors and grid patterns. Manufacturers use different materials to construct the windows, with vinyl being the most popular. Some windows have a low-e coating which reflects heat and reduces energy consumption. And many manufacturers offer the choice of single pane or double pane windows.