What does VLT measure?
VLT is the percentage of visible light transmitted through a material. Lower values mean less light passes through. Measuring glass with film describes the whole combination; the value on a film sample refers to the film alone.
Why does 70% film not mean 70% glass?
Factory glass also blocks some light. A purely mathematical example: 75% glass and 70% film give approximately 0.75 × 0.70 = 52.5%. This illustrates the relationship; it is not a vehicle measurement or a guaranteed product specification.
When should you ask about measurement?
We have a VLT meter and perform measurements. Before visiting, say which windows you want checked and whether they already have film. Agree with us on the measurement scope, whether before-and-after checks are available, and how results will be shared.
- Before choosing film for a windscreen or front side windows.
- When the existing film or factory-glass specifications are unknown.
- When changing light conditions make the shade hard to assess.
What does the result establish?
The result describes light transmission through the tested glass. It is not official certification or type approval. It also does not establish heat protection, installation quality or visibility in every driving situation.
Section 8(5)(4) of Poland’s vehicle technical requirements specifies at least 70% for windscreens and front side windows. Meeting the VLT threshold does not replace checking the other requirements.
Does the same threshold apply at the rear?
The 70% threshold in this provision concerns windscreens and front side glass. Rear windows still require consideration of visibility, required mirrors and other vehicle requirements. It does not make every configuration acceptable.
What should your enquiry include?
Contact Tint Dad about a VLT consultation. The consultation is free. Describe your car, the windows concerned and existing film. We will agree timing and measurement scope when we speak.
Source: Polish regulation Dz.U. 2024 item 502, § 8(5)(4) (PDF)