Understanding Window Condensation for Homebuilders: Causes and Solutions

Window condensation is a topic that often confuses homeowners, leading to questions and even misplaced blame on the quality of windows. As a homebuilder or contractor, you are not only tasked with installing high-quality products like Ply Gem® windows and doors but also explaining the science behind condensation to homeowners. Understanding and communicating the causes and solutions for condensation can strengthen your credibility and ensure customer satisfaction. 

What Causes Window Condensation? 

Contrary to widely held belief, windows do not cause condensation. Instead, condensation forms when warm, humid air encounters a cooler surface—like a windowpane. The air moisture condenses into water droplets, like how a cold beverage “sweats” on a warm day. 

For example, during colder months, the warm, humid indoor air collides with the cold glass surface, resulting in condensation on the inside of the window. This is particularly common in well-insulated, energy-efficient homes where moisture cannot easily escape to the outside. 

Common Types of Condensation 

1. Interior Condensation: This occurs inside the home and is typically a result of high indoor humidity. Activities such as cooking, showering, or even breathing contribute to moisture in the air. 

2. Exterior Condensation: Often seen on the outside of energy-efficient windows, exterior condensation is a sign that the windows are doing their job by preventing heat transfer. 

3. Between the Glass Panes: If condensation forms between double or triple panes, it may indicate a seal failure and should be addressed with a window repair or replacement. 

Why Do New Windows Sometimes Show More Condensation? 

Homeowners may notice more condensation after installing new, energy-efficient windows. This can be perplexing, but the truth is that older, drafty windows allowed moisture to escape. Modern windows, like the Ply Gem brand, are designed to keep indoor air sealed inside, which can trap excess humidity if the home’s ventilation is insufficient. 

Explaining the Science to Homeowners 

Builders and contractors can ease concerns by helping homeowners understand these key points about condensation: 

• Energy Efficiency: Condensation on exterior windows often indicates superior insulation, as the glass surface remains cool due to its separation from indoor warmth. 

• Indoor Humidity Levels: Excess moisture is often the culprit. Encourage homeowners to monitor and control indoor humidity, especially during seasonal temperature changes. 

• Temporary Issues: Condensation is common in newly constructed or renovated homes as materials release trapped moisture. This typically resolves after the first heating season. 

Solutions for Managing Condensation 

While condensation cannot be eliminated, builders can take steps to minimize it and provide homeowners with practical solutions: 

1. Increase Ventilation Recommend installing or using kitchen and bathroom exhaust fans and ensuring they vent to the outdoors. Encourage occasional window opening to let stale, humid air escape.

2. Control Indoor Humidity Homeowners can use a dehumidifier or humidistat to maintain optimal humidity levels. During colder months, recommend the following humidity ranges based on outside temperatures: 

• 20-25% when it’s 0°F 

• 25-30% when it’s 10°F 

• 30-35% when it’s 20°F

3. Proper Window Placement Advise on designs that promote airflow around windows, especially for bay or bow windows where air circulation may be restricted. 

4. Quality Insulated Glass Units (IGUs) Use windows with advanced insulated glass, like the glass packages offered by the Ply Gem brand, which feature technologies such as laminated panes to minimize condensation and improve security. 

Highlighting Advanced Solutions with Ply Gem Windows and Doors 

Ply Gem windows and doors offer industry-leading performance to combat condensation challenges. For example, our insulated glass units (IGUs) feature: 

• Lamination: Providing additional insulation, helps to keep indoor surfaces warm and less prone to condensation. 

• Energy-Efficient Design: Superior insulation keeps outdoor temperatures from affecting the indoor environment, ensuring comfort and reduced condensation. 

Key Takeaways for Builders 

1. Educate Homeowners: Condensation is not a defect, but a natural occurrence tied to humidity and temperature differences. 

2. Promote Ventilation and Humidity Control: Proper airflow and humidity regulation can significantly reduce condensation issues. 

3. Use Advanced Window Technology: Products like Ply Gem windows provide energy efficiency and performance that align with the needs of modern homes. 

4. Highlight Energy Efficiency: Exterior condensation can be reframed as proof of high-performing, energy-efficient windows. 

Conclusion 

For homebuilders and contractors, understanding window condensation is crucial for addressing homeowner concerns and delivering quality installations. By choosing innovative solutions like Ply Gem windows and educating homeowners on proper ventilation and humidity control, you can create comfortable, energy-efficient homes while fostering trust and satisfaction.