Curtain Wall Condensation: Causes, Prevention, and Node Optimization
TIME: 2025-10-11 READ: 18 AUTHOR:
Curtain wall condensation is a common challenge in modern high-end office buildings and residential projects. While transparent and bright curtain walls enhance building aesthetics, condensation on interior glass surfaces, window frames, or metal caps can cause mold growth, material corrosion, and structural issues. This article explains the causes, scientific evaluation methods, and practical strategies for curtain wall condensation prevention.
What is Curtain Wall Condensation?
Condensation occurs when humid indoor air comes into contact with a surface below its dew point temperature, causing water vapor to condense into liquid.
Dew point temperature depends on air temperature and relative humidity. Higher humidity raises the dew point, increasing condensation risk.
Differences in thermal conductivity among curtain wall materials—such as glass, aluminum profiles, thermal breaks, and sealants—can create thermal bridges, leading to localized low surface temperatures that promote condensation.
Key takeaway: Condensation happens whenever the surface temperature falls below the indoor air’s dew point.
Scientific Assessment of Anti-Condensation Performance
Accurate curtain wall condensation analysis relies on thermal principles such as energy conservation, heat transfer, and steady-state temperature fields.
Professional evaluations often use thermal simulation software to model temperature distribution at curtain wall nodes under various environmental conditions, providing data-driven insights for anti-condensation design.
Environmental Parameters for Simulation
Indoor air temperature: 20°C
Outdoor design temperature: based on local winter minimum
Relative humidity: 30%, 50%, 60%
Convective heat transfer coefficient: Indoor 3.6 W/(m²·K), Outdoor 16 W/(m²·K)
Dew Point Reference
At an indoor temperature of 20°C:
Relative HumidityDew Point Temperature30%1.9°C50%9.3°C60%12.0°C
If the interior surface temperature falls below the corresponding dew point, condensation is likely.
Material Thermal Properties
Material thermal conductivity significantly affects curtain wall anti-condensation performance. Variations in conductivity among aluminum profiles, thermal breaks, glass units, and sealants require careful selection and combination to optimize thermal performance and minimize condensation risk.
Node Simulation and Case Study
Thermal simulations for typical curtain wall nodes—beams, columns, operable panels, and decorative fins—identify minimum interior surface temperatures and high-risk areas.
Simulation results often highlight thermal bridges at beam-column intersections and operable panel edges. Targeted optimization of these nodes raises local surface temperatures and reduces condensation risk.
Strategies for Anti-Condensation Design
1.Use Low-Thermal-Conductivity Materials
Nylon or fiberglass thermal breaks
EPDM (ethylene propylene diene monomer) gaskets
2.Optimize Profile Design
Thermal break aluminum profiles
Wider thermal breaks to reduce heat loss and improve temperature distribution
3.Control Indoor Humidity
Dehumidifiers or mechanical ventilation with fresh air supply
Maintain relative humidity in a safe range to lower dew point temperature
4.Enhance Airtightness
Minimize air infiltration
Prevent cold air from contacting interior surfaces directly
5.Node-Specific Optimization
Focus on critical nodes such as beams, columns, and operable panels
Adjust profile structure, thermal break placement, and sealing design to optimize low-temperature areas
Conclusion
Curtain wall condensation prevention is essential for energy efficiency, occupant comfort, and building durability. Through scientific thermal analysis, careful material selection, profile optimization, and node-specific design improvements, cold bridge effects can be minimized, interior surface temperatures increased, and safe, comfortable, and high-performance curtain wall environments achieved.
By integrating these strategies with local climate data and building usage, architects and engineers can create truly condensation-free curtain wall systems that balance aesthetics, comfort, and long-term durability.
