4 Common Double Glazing Problems & Fixes [2024 Guide]

Table Of Contents

Did you know that while double glazing remains one of the most energy-efficient windows and doors, it can also develop problems along the line? These issues not only cost thousands per year in wasted energy but also create an uncomfortable working environment.

The good news is most double glazing problems can be fixed by either replacing certain components or doing a full window replacement. In this guide, we’ll walk you through how to identify common double glazing problems in buildings and the steps to remedy them before they cause real damage.

4 Double Glazing Problems to Watch Out for

According to our guide on how long windows last, the average double-glazed unit has a life span of 10–35 years before needing replacement. However, continuous usage can cause your windows or doors to develop faults earlier. These problems can include condensation, drafts, noise, and fogging or frosting.

1. Condensation Between the Panes

If you notice condensation or water droplets forming in between the two panes of glass, it means the airtight seal has broken. This allows warm, moist air to penetrate the unit and condense. Not only does this obscure your view and let in less light, but the trapped moisture can lead to the growth of mould and damage the entire window, frame or sill.

Check out our guide on how to get rid of condensation between double-glazed windows for potential fixes.

2. Drafts or Air Leaks

The presence of noticeable drafts (unwanted air coming in), especially around the edges of windows, often means the seals or gaskets have perished or shrunk, creating gaps for air infiltration. This results in uncomfortable working conditions and higher energy bills and can even lead to structural damage over time.

3. Noise Transmission

When soundproofing is compromised due to failing window seals, outside noise will easily pass through to the interior. Traffic, loud machinery and other ambient sounds will disrupt concentration and productivity among employees/staff.

4. Fogging and Frosting

If double glazing units are no longer properly insulating, the temperature difference between indoor and outdoor double glazing panes can lead to excessive fogging, frosting and even ice build-up. This obscures natural light, reduces visibility and fresh air, and causes major energy loss.

So, how do you fix these common problems with uPVC windows before they become a major issue? Keep reading to discover simple troubleshooting suggestions.

3 Solutions for Fixing Double Glazing or uPVC Problems

uPVC window problems are an office manager’s nightmare; not only can they disrupt productivity at work, but they can also prove costly if left unattended. But don’t panic just yet; there are several solutions you can try to fix common double glazing issues before resorting to a full replacement. These include sealing or replacing weatherstripping, replacing glazing tape, and reglazing or refurbishing the windows.

1. Seal or Replace Weatherstripping

If there are drafts, air leaks, or moisture getting in around the edges of the window frame, the weatherstripping seal has likely worn out or come loose. Weatherstripping, also known as a window seal or glazing seal, is the insulation around the edges of the window and door frames that helps keep air and water out.

Replacing damaged or worn-out weatherstripping is an easy fix that can improve energy efficiency. You can find weatherstripping kits at any hardware store, or better still, contact a glazing expert.

2. Re-Secure or Replace Glazing Tape

Glazing tape is the sticky tape around the edges of the glass panels that adhere to the window frame. If you notice the glass rattling, slipping or becoming loose in the frame, the glazing tape may need to be re-secured or replaced.

Remove the existing tape with a putty knife or chisel and clean the area. Apply new glazing tape around the edges of the glass and press firmly onto the frame to secure the glass in place.

3. Reglaze Windows

If there are cracks, holes or gaps in the seal between the glass panes and the window or door frame, it’s time to reglaze your windows. Reglazing involves removing the damaged glazing compound, cleaning the area, and applying new glazing to securely seal and weatherproof the glass to the frame. For small cracks, you can apply glazing compound or glazing tape; for more extensive damage, it may be best to hire a glazing replacement expert to ensure it’s done properly.

Double-glazed window problems can significantly impact energy efficiency, temperature control, and the air quality in your building. Fortunately, there are several effective solutions for fixing common double glazing issues before having to completely replace your windows. But at what point exactly do you need a complete window replacement? Read on to find out.

When to Repair vs. Replace Double Glazing Windows

Double glazing is a great way to improve energy efficiency in offices, but the seals and glass can deteriorate over time. When issues arise, it can be difficult to determine whether double glazing repairs or a full replacement is needed. As a general rule of thumb, if problems with double-glazed windows are minor, repair is probably sufficient; for more serious issues, replacement may be required to avoid potential disasters.

When Repair Is Recommended

Here are different 3 scenarios when you should opt for double glazing repair services:

  • Condensation has built up between the glass panes: This indicates the seal has started to fail, allowing moisture to enter. Resealing and re-pressurizing the unit can fix the issue.
  • Small cracks or chips in the glass: Double glazing cracking issues can be fixed by repairs as long as they’re not in the line of vision and don’t impact the structural integrity or insulation.
  • Frame damage or wear: A professional glazier or handyperson can frequently repair minor damage to the frame, sash, or hardware.

When Replacement Is Required

In the following 4 cases, repairs may not cut it, so replacing the entire window may be the way to go:

  • Multiple failed seals or large cracks in the glass: Once a double-glazed window has extensive damage, repair is no longer cost-effective or viable; replacement will be needed to reduce heat loss through the window.
  • The window no longer closes or locks properly: If the window is no longer functioning due to damage, it must be replaced for both energy efficiency and security reasons.
  • Condensation is inside the glass panes, not just between them: This indicates the glazing has completely failed and replacement is urgently needed. If left unattended or attempts to stop condensation fail, moisture trapped inside the glass can damage window frames and sills.
  • The window is more than 25 years old: Even with repairs, older double glazing windows will not achieve the same level of efficiency as new units. For maximum energy savings and comfort, investing in a newly installed double glazing is better in the long run.

Whenever you experience problems with double glazing windows, assess them carefully to determine whether repair or replacement is the best solution. For minor problems, a repair can save money and restore performance; for more serious damage or ageing windows, replacement may be required to avoid problems down the road and keep your office at maximum efficiency and comfort. The choice ultimately comes down to which option will provide the best long-term value.

Add-On: Is Double Glazing the Same as uPVC?

As you’ll notice in this guide and other publications, the terms “double glazing” and “uPVC” are used interchangeably; however, they refer to different aspects of a window. Double glazing involves the fusion of two glass panes for insulation and noise reduction, while uPVC (unplasticised polyvinyl chloride) denotes a durable plastic used for window and door frames.

The main difference lies in their functions. Double glazing enhances thermal efficiency—keeping your office warmer in winter and cooler in summer—and reduces noise pollution. On the other hand, uPVC offers structural durability, low maintenance, and cost-effectiveness for your windows.

In terms of similarities, both are popular for modern office buildings due to their energy efficiency. They can reduce heating bills and increase comfort. When used together, they excel in reducing external noise and boosting office productivity. So, if a glazier refers to a double-glazed window as uPVC, it’s likely due to the window’s structural reinforcement with uPVC.

Frequently Asked Questions

Why is cold air coming through my double-glazed windows?

Cold air might be seeping through your double-glazed windows due to failed seals. These seals, crucial for securing each glass pane, may have sustained damage over time, causing a breach in the insulation, hence permitting chilly drafts to infiltrate your building. Regular inspection and timely repairs can prevent such issues.

Does condensation mean double glazing has failed?

Yes, if condensation is forming between the panes of your double-glazed window, it’s a strong indicator that the seal has failed. This seal breach often results in moisture infiltrating the space between the glass, leading to condensation. Replacement of broken seals should be considered in such cases.

What is the average lifespan of double-glazed windows?

Double-glazed windows typically have a lifespan of around 20 years. However, this can fluctuate between 10 and 35 years and is contingent on the quality of materials used, the installation process, air temperature, and the windows’ location. Therefore, regular maintenance is key to ensuring their longevity.

Can you fix failed double glazing?

While it’s technically possible to repair failed double glazing by renewing the seal, it’s not generally recommended. This fix won’t address the misting or condensation already within the panes, so it’s often more beneficial to replace the entire window.


Double glazing problems reduce the efficiency of your window and door units, so it’s important to take proactive steps to resolve them before they become major issues. We recommend having your double glazing windows inspected regularly for signs of seal failure or broken glass.

In cases where temperatures start to drop consistently or noise pollution increases, it’s possibly time for a replacement. Hiring a glazing professional to replace faulty double glazing may seem like an expense you want to avoid, but it will save you money and hassle in the long run.

No items found.

Newsletter Signup

Signup to receive our email newsletter providing you with the latest GR updates, offers and more.
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.

Book a Site Survey

Book an inspection from the UK’s leading glazing refurbishment company.