Blog > Category Post > Updated: 2017-Dec-19
Visible transmittance (VT - expressed as a number from 0 to 1) also known as Visible light transmission (VLT - expressed as a percentage %) is a measurement of the amount of light in the visible portion of the spectrum that passes through glass. The higher the number, the greater the amount of light that is passing through the glass. VT is the typical measurement used for windows.
Although maximizing the amount of light entering through a window is often desired, especially in colder climates, there is often an undesirable solar heat gain.
High-performance windows with low-E coatings can reject the solar heat gain while allowing relatively high amounts of visible light to pass through the glass, however, the more solar gain being filtered out, the less (minimal) the transmittance. Tints can also be added to glass to decrease light transmittance.
The amount of solar gain can be adjusted to allow more or less light entering the home. The type of low-E coating that is appropriate for your specific house depends on the orientation of the window area, and shading strategies that are being used.
Need help finding understanding visual transmittance, leave the guessing out of it, talk to your local window specialist. They’ll help you find the perfect window, that will maximize your in-home comfort