Visible Light Transmission (VLT) is one of the most important technical parameters when selecting solar control films. It shows how much visible light passes through the film into a room, directly affecting lighting, comfort, and energy efficiency.

How does VLT work?

VLT refers to the percentage of visible light (380-780 nm) that passes through the film. It is measured with a spectrophotometric device, and the value ranges from 0% to 100%:

0% VLT – complete light block (very dark)
100% VLT – complete light transmission (completely transparent)

Visual comfort and productivity

In open offices and commercial spaces, it is essential to ensure a sufficient level of natural light (ideally 40-70% VLT) while maintaining screen visibility and preventing glare. Properly chosen VLT helps create **a more comfortable and productive working environment for employees.

Energy efficiency

Although lower VLT helps block solar radiation and heat more effectively, the relationship is not linear. Therefore, VLT must be considered in relation to the Solar Heat Gain Coefficient (SHGC) to achieve the optimal balance.

When to choose which VLT?

Range	Recommended application
50-70%	Open-plan offices, retail spaces, healthcare facilities, north-facing facades
30-50%	Standard offices, hotel areas, schools, east/west-facing sunlight
15-30%	IT rooms, south-facing windows, privacy-sensitive areas, server rooms

What to consider in design?

• Energy efficiency requirements: Many building codes specify minimum VLT thresholds
• Safety standards: emergency exits must maintain a certain level of visibility
• Certification: VLT helps buildings achieve LEED, BREEAM, and similar energy ratings

Technical inspection before and after installation should include:

Spectral data
Effects of angles on light transmission
Post-installation VLT measurements
Compatibility with existing glazing systems

Contact us if you need:

VLT-based calculations
Project-specific product recommendations
Installation guidelines or documentation

We provide Solar Screen films with:

Accurate spectral data
High-quality technical documentation
Special solutions for large projects
Consultation and training
Certified installers

30.06.2025