When retrofitting or upgrading existing buildings, window frames often become the bottleneck. Replacing entire sash systems is costly, disruptive, and in heritage projects, sometimes not even allowed. HaanGlas Vacuum Insulating Glass (VIG) offers a thin, lightweight, yet high-performance alternative — enabling glass replacement without changing the original frames.
Below are three case studies showing how VIG delivers energy efficiency, compliance, and cost savings — while keeping existing sashes intact.
Case Study 1: Heritage Building Retrofit with Original Timber Frames
In a protected heritage site in Europe, original wooden sashes had to remain untouched. The solution was to replace single glazing with HaanGlas VIG Basic (as thin as 6.3 mm or 8.3 mm). With a thermal transmittance of ~0.47 W/m²·K, the performance leap was remarkable compared to old single panes.
Results:
Warmer interior surfaces, virtually no condensation in winter.
Original aesthetics fully preserved.
Energy loss cut by more than 70%.
For more details, see Retrofitting with Energy-Efficient Vacuum Glazing .
Case Study 2: Aluminum Façade Upgrade in a Commercial Building
A modern office façade required higher performance without dismantling aluminum frames. The team adopted HaanGlas VIG PRO, designed for tight cavities with 25–40 mm pillar spacing.
Project results:
Overall window U-value improved by 30–40%.
Unit weight remained close to double glazing — far lighter than triple-pane IGUs.
Installation was quick, with no sash redesign required.
See Vacuum glazing solutions – PRO.
Case Study 3: Large-Scale High-Rise Curtain Wall
High-rise projects demand large glass panes with minimal added weight. HaanGlas delivers VIG units up to 1600 × 3000 mm, suitable for curtain walls.
In one retrofit project, large VIG panes directly replaced existing glass infills. Because VIG weighs 50% less than triple glazing (15–20 kg/m² vs. 35–40 kg/m²), frames needed no reinforcement.
This made it possible to meet energy targets and extend façade life without major structural changes.
Why VIG Works in Existing Frames
HaanGlas VIG succeeds in retrofits because of its unique design:
Ultra-thin profile: Standard options include 3 + 0.3 V + 3 (6.3 mm) and 8.3 mm constructions.
Thermal efficiency: U-values as low as 0.47 W/m²·K; acoustic insulation up to 36 dB.
Low-temperature edge sealing (<250 °C): Prevents stress cracks, ensures durability.
No exhaust holes: Smooth surface, longer service life.
Optimized micro-pillars: Invisible spacing design reduces visual interference.
Research also confirms this. In studies such as Energy and Thermal Comfort Performance of Vacuum Glazing Retrofit, energy loss reductions of 20–40% were reported, depending on building type and climate.
Benefits at a Glance
No frame redesign required — ideal for retrofits and heritage buildings.
Lightweight yet high performance — easier shipping and installation than triple glazing.
Future-proof — already compliant with 2026 U-value requirements in markets like Ontario and Scandinavia.
Preserves aesthetics — crucial for historic façades and sensitive architecture.
Conclusion & Call to Action
These case studies prove that HaanGlas VIG makes retrofits and heritage upgrades practical, affordable, and high-performing — all without redesigning frames.
If you’re planning a retrofit or façade upgrade, visit our Contact Page to request cross-section drawings, case studies, or installation brochures tailored to your project.
