Various types of glass are used to make dual-pane windows. Tempered glass is also an option and may even be a requirement depending on the window and region. Tempered glass is heat-treated such that in case the window shatters, injuries are minimized. Usually, the glass sheet is heated to a certain temperature then cooled rapidly. That way, the outside, and edges cool quickly and compress than the center to strengthen the sheet. Tempered glass breaks into rounded granules if shattered, unlike other types of glass that break into jagged shards. Depending on your region, you will be required to use tempered glass in certain areas of your home: Usually in zones of close human contact, close to a golf course, etc.