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4 Warning Signs: How To Tell If Your Double Glazing Has Failed

How To Tell If Your Double Glazing Has Failed

4 Warning Signs: How To Tell If Your Double Glazing Has Failed 

Double glazing is a popular feature among households because it provides thermal insulation, noise reduction and overall improved security. 

However, double glazing can fail over time which can affect its effectiveness and cause a range of issues. Immediate action is best to save your windows from total break, but sometimes problems are not obvious to homeowners. 

In this article, we’ll list down the signs on how to tell if your double glazing has failed, the reason why they did and the potential repair cost you’ll spend fixing them. 

Why Do Double Glazing Units Fail

Different reasons could make your double glazed windows fail, and understanding these factors can help you prevent them. Here are the common reasons for failed double glazing units. 

  • Age: Your double glazed windows will age over time. When it happens, the seals can break down, allowing moisture to pass through the window panes and cause condensation. 
  • Poor Installation: Incorrect installation can lead to early double glazing failure. Proper installation ensures the lifespan of your window. It’s best to seek professional help for installing your windows. 
  • Physical Damage: Powerful impacts can accidentally damage your windows. It can weaken the seal and its other components, which will cause double glazing failure. 
  • Environmental Factors: Extreme weather variations and constant exposure to intense temperatures can accelerate the deterioration of your windows. 

How To Tell If Your Double Glazing Has Failed 

A double glazing window starts to fail when the seal between the glass panes breaks. However, the gaps in the sealing are not easily spotted. So, what happens when double glazing fails?

Condensation Between Panes

One of the most obvious signs of failed double glazing is the presence of condensation or fogging between the glass panes. The moisture build-up indicates damage to the airtight seal, which reduces the insulating properties of the windows.

The gaps between the windows should be sealed properly to serve as a moisture barrier to enhance the insulation of your windows and prevent condensation. 

Reduced Thermal Efficiency 

The thermal efficiency of double glazed window significantly decreases when it fails. This will mean that your windows can no longer keep the cold air out during the winter and hot air during the summer. As a result, it could lead to an uncomfortable indoor environment and higher electricity bills. 

Drafts and Cold Spots

Drafts are the unwanted flow of cold air that passes through your living spaces. Cold spots pertain to certain spaces in your home that are colder than the surrounding areas. These issues are common among households with failed double glazed windows. 

UV Damage

Ultraviolet rays (UV) can infiltrate your home when double glazing fails. UV rays are not visible to the eye, but they are powerful enough to cause damage to furniture. Overexposure to UV rays can lead to the fading of your decorative items, such as carpets, curtains and other objects in your house. 

Failed Double Glazing Repair Cost

The repair cost of failed double glazing units depends on the extent of the window’s damage. Here are some factors that can affect your repair expenses.  

  • Seal Replacement: Damages on the seals are minor issues that can be addressed by resealing or completely coating your window with a new one. Depending on the number of windows, this could cost up to a few hundred dollars. 
  • Partial Unit Replacement: You might need to replace certain parts of the double glazing unit in cases where damage is more severe. The price for each window could vary from $300 to $600.
  • Full Unit Replacement: You may need to replace the entire window if it is beyond repair. Depending on the size and style, a single replacement unit can cost between $500 to $1,000.


Maintaining a cosy and energy-efficient home requires knowing the warning signs of failed double glazing. Consult a specialist for an evaluation if you notice dampness, drafts, or decreased heat efficiency.

Even though the repair of double glazing might be expensive, the comfort and energy savings it provides over time make it a practical investment in the general well-being of your home. 

If you’re looking for a professional double glazing installer, Nu-Eco is at your service. Contact us today and get a free measure and quote.

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