The term double or triple glazing refers to insulated glass units (IGUs) that contain two or three panes of glass separated by an air space. With Blackline Aluminum's double/triple glazing, low-emissivity coatings (Low-E) can further enhance energy efficiency. These coatings reflect heat back into the building in cold weather; in hot weather, they block it from entering. A common way to reduce heating and cooling costs in residential and commercial buildings is to use double and triple glazing. Additionally, they can offer other benefits such as noise reduction and improved comfort.