Glass coatings are employed either to reject the amount of heat entering a building or to reduce the amount of heat transfer from within the building. Accordingly, coated glasses can be designed and manufactured to reduce either direct heat from the sun passing through the glass (near infra-red short-wave energy) or absorbed and radiated heat from both inside and outside the building (far infra-red long-wave energy).Different types of coatings including Heat MirrorTM coating technology can be used in conjunction to deal with short and long-wave energy problems. Coatings can either take the form of a layer of metal oxides incorporated during the manufacturing process (pyrolytic coating) or be applied in a controlled environment by the evaporation of different typed of metals (sputter coating).The end product generally has an enhanced, more reflective appearance, coatings with a less reflective appearance, which permit more light to enter, are now considered more desirable and increasingly available.

Highly reflective coatings are useful to achieve uniformity in curtain wall facades and where privacy is required during the day. At night, however, necessary internal building illumination will enable the interior to be seen from the outside, whilst the glass when viewed internally will have the disadvantage of appearing as a mirror to the occupants when looking out, and in consequence spoil the view.