What is a good visible transmittance rating?
between 0.30 and 0.70
While VT theoretically varies between 0 and 1, most values among double- and triple-pane windows are between 0.30 and 0.70. The higher the VT, the more light is transmitted. A high VT is desirable to maximize daylight.
What is visible light transmittance?
Visible Light Transmission (VLT) is a measurement of the amount of visible light waves that transmit through a material. Measured as a percentage, VLT values for vision glazing, like insulated glass units (IGU) that transmits a direct beam of light, typically range between 40-70%.
What is visible light transmission percentage?
Visible Light Transmittance (VLT) describes the percentage of visible light (approximately 390 to 780 nanometers within the solar spectrum) transmitted through the glass. It is determined by the glass color and thickness. Clear float glass has 75% to 92% VLT; colored glass has 14% to 85% VLT.
What does high light transmittance mean?
The higher the VLT percentage is, the lighter the lens tint will be. Higher VLT percentage lenses will allow for more light to travel through the lens that will then hit the eye. Alternatively, lenses with a lower VLT percentage will have a darker tint and will block more light from coming through to the eye.
What is a good VT for a window?
Most double- and triple-glazed windows have VT values between 0.30 and 0.70. Higher VT is desirable, but lower VT values are often delivered along with lower U-factors. If you get a really high-performing window, beware of VT values less than 0.40. Below that point, your view may start to have a grayish cast.
What is the best solar heat gain coefficient?
For the “passive solar” effect, choose an SHGC value between 0.42 and 0.63. For true solar heating, choose the highest value rating you can find.
What are G values?
What is g-value? The g-value is a measure of how much solar heat (infrared radiation) is allowed in through a particular part of a building. A low g-value indicates that a window lets through a low percentage of the solar heat.
What is visible light reflectance?
Visible Light Reflectance (VLR) – is the measurable amount of visible light that is reflected out by a glazing system. A glazing system with a high VLR means that most of the daylight is not passing through the window. The VLR for a piece of untinted glass is very small—about 6%.
What does 70 VLT mean?
Tint Darkness. For example, if you apply a tint of 70% VLT, it allows 70% of sunlight to pass through your windows. Therefore, it only blocks 30% of the sun. The darker the film you apply, the lower the amount of light that can get through will be — more light will be reflected off your window.
What does 30% tint mean?
30% tint means that the window tint allows 30% of the light to shine through the glass once applied. In other words, 30% tint blocks 70% of the light from passing through the glass. The tint percentage refers to Visible light transmission (VLT) which is how much light a window film allows to pass through.
What is light transmissivity?
Transmissivity is an optical property of a material, which describes how much light is transmitted through material in relation to an amount of light incident on the material. The light that was not transmitted was either reflected or absorbed.
How do you calculate transmission light?
It is defined as T = I/Io, where I = transmitted light (“output”) and Io = incident light (“input”). %T is merely (I/Io) x 100. For example, if T = 0.25, then %T = 25%.