Architectural glass light in industrial factories. Annealed glass is glass without internal stresses caused by heat treatment, i.e., rapid cooling, or by toughening or heat strengthening. Glass becomes annealed if it is heated above a transition point then allowed to cool slowly, without being quenched. Float glass is annealed during the process of manufacture. However, most toughened glass is made from float glass that has been specially heat-treated. Annealed glass breaks into large, jagged shards that can cause serious injury and is considered a hazard in architectural applications. Building codes in many parts of the world restrict the use of annealed glass
Heated glass 30 years to prevent condensation and provide radiant heat. Condensation in buildings can have serious consequences to health and property values. Heated or radiant glass is generally an enhanced standard two pane insulated glass window using various bus bar technologies to convey the electric current to heat the glass. Some technologies are patented and permit larger glass areas to be heated than others. In One university study shows that this heated glass technology is more efficient than other electric heating and can be more efficient than natural gas heating. Some environmentalists dispute the idea that this is an efficient heating