What does VLT mean?
Visible Light Transmission describes how much light passes through the glass and film together. A higher percentage is lighter; a lower percentage is darker. The film label is not always the finished measurement because factory glass affects the result.
The main WA limits
Windows forward of the B-pillar generally need at least 35% luminous transmittance. Rear glazing may be reduced to at least 20% where compliant external rear-view mirrors are fitted on both sides. Windscreen film is generally not permitted, apart from the limited upper band area allowed by the rules. Reflectance must not exceed 10%.
Practical questions to ask
Ask whether the quoted percentage refers to the film alone or the finished glass-and-film result. Tell the installer if you drive at night, and mention existing privacy glass or old film. The darkest-looking option is not always the most comfortable or practical option.
Perth Tint Co. can explain suitable film and shade options for cars, SUVs, 4WDs, utes and vans.