How do Solar Control Window Tinting Films Work?
How do Solar Control Window Tinting Films Work?
Heat is energy from the sun. This energy is in the form of ultraviolet (UV), visible light, and infrared (IR) radiation. These different forms of radiation have different wavelengths measured in nanometres (nm) as shown in this diagram.
Some of this energy we want in our home and some we would prefer to keep out.
- Visible light stops our home feeling dark, but too much light (glare) is uncomfortable.
- Ultraviolet light causes furniture, carpets and curtains to fade and can damage our skin and eyes so it is best to keep this out.
- Infrared radiation keeps us warm, but too much can make our home feel hot.
- Many products have been developed to control the effects of the sun.
- Window tinting is the most popular and cost effective option.
Solar energy reaches Earth in the form of visible light, UV and Infrared. (Slightly less than 50% of total solar energy is in the form of visible light). When solar energy strikes a solid object it is converted into heat energy. Yes, visible light also causes heat.
- Window tinting film reduces the heat that enters a room through windows. A film’s heat reducing performance is measured as a percentage of the Total Solar Energy that the film Rejects (TSER).
Standard window tinting films either reflect the solar energy away from the window (eg Mirror Tint) or block the solar energy by shading the window (much like shade cloth).
- Standard window tinting films block (or reflect) all three forms of solar energy in equal part. They do not distinguish between the visible light that we want in our home and the UV and infrared that we want to keep out. This means a standard window tinting film that achieves high heat reduction will also block most of the visible light, and make a home “feel” dark. This is the basis for the myth that only a dark film will block the heat.
Standard window films are a popular choice in commercial buildings because they achieve high heat reduction at relatively low cost, and any loss of natural light is compensated by the use of artificial lighting. However, most homeowners do not want a home that “feels” dark nor do they want to turn on lights during the day and new “smart” films were developed to meet the priorities of homeowners. Rather than blocking the infrared, UV and the visible light equally, Smart Films are designed to block as much of the invisible spectrum as possible (infrared and UV) while blocking only as much visible light as required for comfort.
- Clearly, the more visible light that is blocked, the more heat is also blocked, however, if too much light is blocked it will make the home “feel” dark and uninviting, which most people wish to avoid.
- By blocking more of the invisible spectrum than standard window tinting films, Smart Films can let in more visible light and still achieve a similar Total Solar Energy Rejected (TSER) as a standard film.
Will Window Tinting make my Home feel Dark?
It has long been recognised that solar energy can be reflected away from a window and the earliest window films were highly reflective (eg. Mirror Tint). These films were very effective at blocking heat but they also blocked the light and many people didn’t like their shiny appearance.
Film manufacturers then made films that were non-reflective. These films absorbed the heat into the glazing system and re-radiated much of the heat outside. These films worked by shading the windows from the sun (much like shade cloth) which meant that films that achieved the highest heat reduction also blocked the most light, and many people complained that it made their home feel dark.
How do Smart Films control the Sun?
The latest technology Smart Films are made from exotic materials with unique spectral properties (ie. materials that will block or transmit solar energy depending on the wavelength). This means Smart Films can block the heat (wavelengths 700 – 2100 nanometres) and the ultraviolet (wavelengths 280 – 400 nanometres) but let through visible light (wavelengths 400 – 700 nanometres) so your home won’t feel dark.
Spectrally selective Smart Films achieve high heat reduction by selectively blocking parts of the light spectrum. The wavelengths associated with infrared and ultraviolet light are blocked while visible light is allowed to pass through. This means a clear spectrally selective film can achieve quite high heat reduction. However, a clear window tinting film will not provide the glare reduction or the privacy some people may seek. Smart Films Ambiance 25 film blocks 75% of the infrared and 99% of the ultraviolet spectrum and blocks only as much natural light necessary to eliminate harsh glare and provide privacy. This window tinting film does reduce the level of natural light entering a room but the reduction is not discernable to most people. The film creates what most people describe as a softer, more pleasant, lighting environment – hence the film name Ambiance.
Smart Films offer a no compromise solution to heat, glare and fading. There is a Smart Film to fulfil the specific requirements of most people. What are your priorities?