Performance and Certification


In modern tightly sealed and highly insulated buildings, achieving proper ventilation can be challenging without deliberate intention. In contrast, traditional Korean Hanok houses, though less energy-efficient due to weaker seals and insulation, naturally maintain pleasant indoor air quality by means of continuous ventilation via gaps. To address issues like sick building syndrome, condensation, and mold in contemporary buildings, proper ventilation is crucial. Especially in spaces with high occupancy rates like offices, commercial establishments, schools, healthcare facilities, etc., continuous ventilation is essential to reduce indoor carbon dioxide levels and virus concentrations. UBLO's sustainable natural ventilation system provides continuous airflow without significantly affecting indoor temperatures. For more in-depth insights into the ideal ventilation conditions based on the positioning of the circular window, refer to the CFD simulation link in the "Learn More" section.

+ Technical Brochure | Ventilation

Wind Pressure Resistance   Performance: 3600Pa

Glass Structural Simulation at 3600Pa pressure

UBLO's 180mm glass aperture and circular window system are engineered for safety against strong winds The glass thickness and specifications are determined through structural engineering based on factors such as glass size, stabilization and reinforcement methods, and aperture locations. The inset frame, engineered for safety, is securely attached to the glass using a double-sealed structure, and the lid is firmly fixed to the inset frame through compressed gaskets. UBLO passed KS F 2296:2019 test , achieving top-grade wind resistance at 360 degrees and 3600Pa pressure.

+ Technical Brochure | Structural Safety

Insulation   Performance: 1.476 W/m2K

The circular windows are engineered with high-quality insulation in mind, utilizing plastic and rubber materials to ensure impressive thermal performance without any compromising metal components. Inside the lid, a double air layer further elevates insulation capabilities, and UBLO also offers the option to fill the lid with a premium insulation option of semi-transparent Aerogel filling. The double glazed UBLO window set achieved a Uw heat transfer coefficient value of 1.476 W/m²K through testing according to KS F2278:2017. The installation of the two circular windows for the test was carried out on double glazed, low emissivity glass (Ug = 1.149 W/m²K) within a 1.5m x 1.5m aluminum insulated frame assembly.

+ Technical Brochure | Thermal Performance

Airtightness   Performance: Lv.1

The glass and inset frame are airtightly joined in a double structure, and when the window is closed with the lid, the EPDM inner gasket on the inset frame is compressed to maintain airtightness. UBLO has successfully passed the KS F2292:2019 test, demonstrating no leakage under the highest pressure of 100Pa, and has achieved KOLAS Air Tightness Grade 1 accreditation.

Watertightness   Performance: Lv.50

External water is drained through the protruding inset frame on the outer glass surface and its lower drainage holes. The glass and inset frame form a dual waterproof structure and an equal pressure space, while the inset frame and lid are pressed with internal gaskets to maintain watertightness. The UBLO window set has passed the KS F 2293:2008 test with the highest grade of watertightness, Grade 50 (test pressure 500Pa).


During the winter, a decline in the product's insulation performance can lead to surface condensation. According to the KS F 2295 standard, condensation may occur when the indoor surface temperature drops to 9 degrees Celsius. To ensure a condensation-free environment, Aerogel insulation material is added to the lid of a circular window. Through heat analysis simulation at -10 degrees Celsius externally and 20 degrees Celsius internally with 50% relative humidity, both the circular window and glass surface temperatures stayed above 9 degrees Celsius, mitigating the occurrence of condensation due to insulation performance. During the fabrication of perforated glass, strict quality control is implemented to prevent condensation and moisture infiltration. Insulation gaskets are also applied around the edges and at the apertures in the glass to enhance its thermal performance.


Selected for Technology Development Product Test Purchase System

Product Name: UBLO Window Set
Specification: Manual Basic Type
Test Purchase Support Period: 2021.07.20 - 2023.11.18

Venture Nation

Registered Product: Circular Window
Product Components: Inset Frame, Lid, Filter

* Venture Nation: a online platform where public businesses and governments can buy items

Good Design Korea Excellent Industrial Design Award Product

Selected Product: UBLO Window Set
Selection Number: G2020A04_00173

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