There are generally 2 of glass used in skylights, tempered glass, and safety laminated glass. Tempered glass has an additional degree of hardness that makes the glass shatter into small pieces rather than large shards of glass when it breaks. Whereas, laminated safety glass is a combination of two pieces of heat-strengthened glass bonded together with a plastic (PVB) inner layer that holds the glass together if it gets broken.

When direct sunlight penetrates into a room, it makes it warmer. This is the case whether light enters through a window, a glass door, or a skylight. However, not every skylight will heat a room during sunny weather, and various factors such as skylight placement and the use of window treatments can affect heat transfer.

Skylights that are positioned properly can let the maximum amount of light into a room without substantially increasing its heat. A skilled architect and daylighting contractor can place skylights and other large window installations to let in light without letting in excess amounts of heat.