Single glazing and double glazing glasses are available for improved heat insulation. Single glazing means just a single layer of glass. In case of double glazing, it means two panes of glass. Since double glazed glasses have two panes, they are certainly more effective than single layered. In making glazed windows, different varieties of glass are used. The infographic http://randburg-glass.co.za discusses about the different kinds of glass available. Standard glass is the regular glass which is often used. Heat efficient glass is used for double glazing. Inert gas is usually packed in the space which lies between glass panes. Solar controlled glass helps in maintaining the room temperature by effective prevention of heat flow out. A strong glass is often used for strengthening windows. Shatterproof glass is used in areas which are struck by hurricanes. Tempered glasses are often used in glazed doors. The kind of glass used is quite dependent and should be used as per the region of use.