What is the Blown Seal Condition in Your Double-Pane Glass Windows that Needs Repair?

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Home What is the Blown Seal Condition in Your Double-Pane Glass Windows that Needs Repair?

Double-pane windows, also known as insulated glass units (IGUs), offer numerous benefits, such as enhanced energy efficiency, noise reduction, and improved insulation. However, these windows can develop a common issue known as a blown seal over time. Blown seals occur when the seal between the glass panes fails, leading to various problems like condensation, foggy appearance, and reduced thermal performance. This blog will delve into the blown seal condition in your double-pane glass windows, understand its causes, and highlight the importance of timely repair.

Understanding Blown Seals:

A blown seal refers to the failure of the seal that separates the two glass panes in a double-pane window. This seal is typically made of a durable material like silicone or butyl and maintains an airtight barrier between the panes. When the seal deteriorates or becomes compromised, air and moisture enter the space between the glass, leading to several issues.


Causes of Blown Seals:

Blown seals can occur due to a variety of factors, including:

  • Aging and Weathering:

    Over time, exposure to fluctuating temperatures, UV radiation, and weather conditions can cause the seal to degrade and lose its elasticity. This deterioration weakens the seal’s ability to withstand pressure changes and environmental stressors.

  • Poor Manufacturing or Installation:

    In some cases, the blown seal condition may result from manufacturing defects or improper installation. If the sealant used during manufacturing is of low quality or the windows need to be installed correctly, it can lead to premature seal failure.

  • Structural Movements:

    Buildings naturally experience structural movements due to settling, vibrations, or shifts in the foundation. These movements can stress the windows, potentially compromising the seals and leading to blown seals.


Consequences of Blown Seals:

When a seal fails, and a blown seal condition occurs, several noticeable issues may arise:

  • Condensation:

    Moisture trapped between the glass panes can lead to condensation, causing a foggy or hazy appearance on the window surface. This not only obstructs your view but also indicates reduced thermal efficiency.

  • Energy Inefficiency:

    Blown seals compromise the insulating properties of double-pane windows, allowing heat transfer between the interior and exterior spaces. This can increase energy consumption and raise heating or cooling costs.

  • Aesthetics and Property Value:

    Foggy or hazy windows can significantly impact the aesthetic appeal of your property, diminishing its overall value and visual appeal.

Importance of Repairing Blown Seals:

Instead of opting for a complete window replacement, repairing blown seals in double-pane windows offers several benefits:

  • Cost-Effective Solution:

    Repairing blown seals is a more economical option compared to window replacement, allowing you to address the issue without breaking the bank.

  • Enhanced Energy Efficiency:

    By repairing blown seals, you can restore the thermal performance of your windows, improving energy efficiency and reducing heating and cooling costs.

  • Clear Visibility:

    Foggy or hazy windows can obstruct natural light and limit your view. Repairing the blown seals restores clarity, allowing you to enjoy unobstructed views and brightening your living or working space.

  • Sustainability:

    Opting for repair instead of replacement aligns with sustainable practices by minimizing waste and reducing the environmental impact of window replacements.



Blown seals in double-pane glass windows are a common issue that can lead to condensation, reduced energy efficiency, and compromised aesthetics. Understanding the causes and consequences of blown seals highlights the importance of timely repair. By addressing the blown seal condition, you can restore your windows’ functionality, clarity, and energy efficiency, while avoiding the significant costs and disruptions associated with window replacement.

Consult a professional window repair service to assess and repair the blown seals in your double-pane windows, ensuring a comfortable and visually appealing environment for your home or business.

Reach out to Window Medics for window glass repair services in Ottawa. Contact the experts at 613-519-1317 or write an email to ottawa@windowmedics.com.

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