The concept of window film for use in solar control flat glass application dates back to the early 1960s. At that time, the main objective was to control the heating and cooling imbalances that result from solar loading. Such early films were found to reflect solar radiation back from a window, preventing the warming of inside surfaces normally hit by direct sunlight while still allowing vision through the glass.
As the window film concept was developed and improved upon, a demand developed for coloured sun control film that would complement architectural design. Coloration of film was achieved through various means to produce colours such as bronze, grey, gold, amber, etc.
The energy crisis of the early 1970s prompted an interest in another aspect of window film use: the reduction of heat loss to the outside. It was discovered that polyester film tended to absorb and reradiate long wave infrared heat rather than act as a transparent medium. Through experimentation, new film materials and constructions were developed that enhanced this characteristic. These films greatly improved heat retention within a room's interior.
With escalating energy costs, products such as window film are increasingly valuable as an investment for commercial and residential owners and commercial facility managers. Apart from potential cost and commissioning savings, from a green perspective, choosing window film has less of an environmental impact than creating a new window and disposing of the old one. Window film, both carbon- and cost-effective, reduces a building’s carbon footprint more effectively and at a lower cost than new windows. When looking to renovate an existing structure to achieve a high-performance building envelope, window film installation should be included among other retrofit upgrades.