Modern construction prizes insulation and airtightness, yet ventilation continues to be the necessary trade-off — the window has to open, even if it undermines the gains. That is changing. At Step Change 2025, Glaston and startup UBLO introduced a bold alternative—a window opening built into the insulating glass unit via a transparent lid, eliminating the conventional frame altogether. It is a radical step toward integrating ventilation and thermal control.
The UBLO system embeds a circular (or custom shape) aperture within an IGU, paired with a smart, insulated lid that can open or close. The lid is engineered to maintain thermal integrity—employing materials such as aerogel—to avoid undermining the U‑value of the unit when used. Earlier prototypes relied on external silicone mounting; the latest iteration uses dry internal mounting, streamlining retrofit and reducing complexity. The system has passed European window performance tests, and is especially pitched at cold climates, where ventilation demand competes directly with the need to minimise heat loss.
For glass fabricators and IGU manufacturers, UBLO presents both opportunity and challenge. The approach demands precision hole cutting, robust edge sealing, consistent coating performance, and structural integrity despite perforation. It also requires integration with spacer bars, gas fills and sealing systems engineered to avoid leaks or condensation at the aperture. On the lid side, reliable actuation and durability under weather cycles will be critical. Success hinges on scaling these to industrial volumes and coordinating across supply chains. Specifiers will likely ask: how does it perform long term, how safe is it, and how does it compare in cost to traditional openers?
UBLO is not alone. Alternatives include micro‑vent modules, push‑out vents, window‑integrated ventilators, and advanced mechanical systems. Yet few combine no visible sash, high transparency, and thermal neutrality in a single concept. If UBLO can prove reliability, it may force a rethink in how ventilation is integrated in high‑performance façades. Window system houses may need to furnish frames pre‑cut for modular aperture units. Glass processors may retool to incorporate precision perforation and dynamic sealing. The mesa of competition will shift from coatings and layers to integrated mechanical/thermal design.
Adoption will depend heavily on cost, durability, reliability, maintenance, and product warranties. A ventilation lid is a mechanical moving part, subject to wear, sealing degradation and mechanical failure. Integration with fire, safety and escape regulation will also require scrutiny. In retrofit scenarios, frame compatibility or structural reinforcement may be limiting. Market conservatism in the window sector could slow uptake unless early high‑profile installations succeed.
If the concept holds up through field trials, the implications are profound: the window becomes a dynamic interface—sealed when closed, breathing when open—without visible sash. Instead of configuring frames and operables, architects and engineers may simply specify “ventilated IGU units.” More broadly, the industry would shift from adding operable hardware to embedding function within the glass itself. In that evolution lies a new frontier for façade innovation—where ventilation, daylight and thermal performance converge seamlessly.
https://ublo-window.com/Home-ENG
Why This Matters: The concept of ventilated IGU units is a very logical idea and the question is, why hasn’t this been thought of before and why isn’t it a mainstream product. UBLO are leading this innovation and the signs are the product is gathering momentum. It’s logical and it is hoped the field trials will further its market penetration and viability.
