Low-U-value aluminum casement windows are a type of building window and door product that achieves high efficiency and energy saving by optimizing thermal insulation performance. Its U value (heat transfer coefficient) is usually less than 0.3 W/(m²·K), which is much lower than the 1.8-3.0 W/(m²·K) of ordinary aluminum alloy windows.

Thermal Break Aluminum Casement Windows Technical Features and Data
Ultra-low U value
Using thermal-break aluminum alloy profiles (PA66 nylon insulation strips) and three-glass two-chamber Low-E glass (6mm+12A+6mm+12A+6mm), the U value can be as low as 0.24 W/(m²·K). For example, the actual U value of a certain brand product is 0.26 W/(m²·K), which is more than 70% energy-saving compared to ordinary single-layer glass windows.
High Solar Heat Gain Coefficient (SHGC) Control
Through Low-E coating technology, the SHGC value can be adjusted from 0.14 to 0.6. For example, areas with high heating demand in winter can choose glass with SHGC 0.6, while areas with hot summers can choose SHGC 0.14 configuration to achieve year-round energy efficiency optimization.
High air tightness and water tightness
Multiple EPDM rubber sealing strips with hidden drainage design, air tightness reaches national standard level 8 (≤0.5m³/(m·h)), and water tightness ≥600Pa. For example, the project passed the salt spray test (≥1000 hours) and wind pressure test (≥4500Pa), ensuring long-term use without leakage in coastal areas.
Long life and low maintenance
The wall thickness of the profile is 1.4-2.0mm, and the surface treatment adopts powder spraying or fluorocarbon coating, with weather resistance of more than 20 years. After 10 years of use, the surface gloss of the profile still maintains more than 85% of the initial value.

Energy Saving Aluminum Casement Window Core Application Scenarios
Heating buildings in cold climate zones
In regions such as Northern Europe or Canada, low U-value casement windows can reduce winter heating energy consumption. For example, a passive house project uses a casement window with a U value of 0.24 W/(m²·K), and the annual heating energy consumption is reduced to 15kWh/(m²·a), which is 80% energy-saving compared with ordinary buildings.
Cooling buildings in tropical climate zones
In the Middle East or Southeast Asia, solar radiation heat is reduced by Low-E glass and warm edge spacers. For example, a Dubai hotel project uses a glass configuration of SHGC 0.14, which reduces the air conditioning load in summer by 30%, saving more than $50,000 in annual electricity bills.
Noise-sensitive areas
The casement window using laminated insulating glass (6mm+0.76PVB+6mm+12A+6mm) can achieve a sound insulation performance of 45dB. For example, a residential project near an airport uses this configuration to reduce indoor noise from 75dB to 30dB, meeting the residential noise standards recommended by WHO.
High-rise and super-high-rise buildings
Casement windows with wind pressure resistance ≥4500Pa can be adapted to buildings over 300 meters. For example, the Shanghai Tower uses customized casement windows, which are verified by wind tunnel tests to have a window deformation of ≤2mm under a typhoon of level 12.

Custom Aluminum Windows Adaptable Building Types
Passive House
Must meet the standards of U value ≤0.8 W/(m²·K) and air tightness ≤0.6 ACH 50Pa. For example, a passive house project in Germany uses casement windows with a U value of 0.24 W/(m²·K) to achieve an annual primary energy demand of ≤120kWh/(m²·a).
Net-Zero Energy Building
Through the combination of photovoltaic curtain walls and low-U-value casement windows, the building energy consumption is self-sufficient. For example, a zero-energy office building uses a casement window with a U value of 0.26 W/(m²·K), and with a rooftop photovoltaic system, the annual net energy consumption is zero.
High-end residences and villas
Large-size (such as 1500mm×3500mm) casement window design meets the lighting and landscape requirements. The sea view villa project uses Low-E glass and electric shading system to achieve dynamic adjustment of 70% light transmittance in winter and 0.2 shading coefficient in summer.
Commercial complexes and hotels
Fire and anti-theft performance must meet commercial standards. For example, five-star hotels use C-level anti-theft lock points and fire-resistant glass (fire resistance integrity ≥ 60 minutes), which are certified by EN 1630 and GB 15763.1.

Aluminum Alloy Windows Procurement Recommendations
Budget-limited projects: Choose 1.4mm profile + double-layer hollow Low-E glass, U value ≤ 0.3 W/(m²·K), unit price 60−90/m².
High-end customized projects: Use 2.0mm profile + three-glass two-cavity argon-filled glass, U value ≤ 0.24 W/(m²·K), unit price 120−200/m².
Certification and warranty: Priority is given to products certified by PHI (Passive House Institute), NFRC (North America), and CE (European Union), with a warranty period of ≥10 years.