Picture this: you’re about to leave for work on a cold morning when you notice it – that telltale misting between your glass panes that wasn’t there yesterday. If you’re facing blown double glazing, you’re not alone. This common issue affects thousands of UK homeowners each year, leading to increased heating bills and decreased home comfort.

Blown double glazed windows aren’t just an eyesore, they’re literally allowing your hard earned money to escape through deteriorating window seals. Whether you’re dealing with a single misted up window or multiple blown double glazed units, understanding your options can save you hundreds in unnecessary replacement costs.

Key Takeaways

  • Early detection of blown double glazing can prevent extensive damage and save significant repair costs.
  • Most double glazing issues can be resolved without requiring a full window replacement.
  • Professional assessment is crucial for determining the most cost effective solution for your specific situation.

What Exactly is Blown Double Glazing?

Blown Windows

To understand blown double glazing, we need to first look at how a properly functioning double glazed unit works. Modern double glazed windows consist of two glass panes separated by a thermally efficient spacer bar. This creates an insulating barrier – a sealed unit filled with either argon gas or dehydrated air that helps maintain your home’s energy efficiency.

When double glazing becomes “blown,” it means the seal between these two panes has failed. This allows the insulating gas to escape and moisture-laden fresh air to enter the cavity. The result? That frustrating foggy or misty appearance between the panes that no amount of cleaning can fix.

The most common signs your double glazing has blown include:

  • Visible condensation or misting between the glass panes
  • Windows that appear cloudy or foggy, especially during temperature changes
  • Water droplets trapped between the two glass panes
  • Noticeable decrease in your windows’ noise reduction capabilities
  • Increased heating bills due to poor insulation

Common Causes of Blown Double Glazing

Understanding why double glazing fails is crucial for both prevention and choosing the right solution. Several factors can compromise your double glazed unit’s integrity, from everyday wear to environmental stresses.

Age-Related Deterioration

Like any home component, double glazed windows have a natural lifespan. Most sealed units are designed to last 15-20 years, but window seals can begin deteriorating sooner due to constant exposure to temperature changes. As your double glazing ages, the risk of seal failure increases, particularly if the windows haven’t been properly maintained.

Weather and Temperature Impact

One of the most significant stress factors for double glazed windows is the constant expansion and contraction of the glass panes and frame materials. When warm air inside your home meets cold air outside, it creates pressure on the seals. This daily thermal stress, combined with heavy morning dew condensing on the glass, gradually weakens the unit’s seals.

Installation Issues

Poor installation is a leading cause of premature seal failure. If your double glazed unit wasn’t fitted correctly, it might suffer from:

  • Improper drainage around the window frame
  • Misaligned glass panes
  • Incorrectly sized units creating unnecessary pressure
  • Damaged seals during installation

Modern Living Patterns

An often-overlooked factor is how modern living affects double glazing performance. Today’s energy-efficient homes are more airtight than ever, which can lead to:

  • Higher humidity levels inside the home
  • Greater temperature differences between inside and outside
  • Increased pressure on window seals due to modern heating systems
  • More frequent use of cleaning products that might degrade seals over time

External Factors

Additional causes include:

  • Physical damage to the frame or glass unit
  • Harsh chemical cleaners degrading the seals
  • Blocked drainage channels in the window frame
  • Excessive solar gain causing seal deterioration

Professional Solutions vs DIY Approaches

When faced with blown double glazing, homeowners often wonder whether to attempt a DIY fix or turn to professional double glazing installation. Let’s examine your options to help you make an informed decision about fixing those misted double glazed windows.

Professional Replacement Options

Most industry experts recommend professional replacement of the double glazed unit rather than repairs. Here’s why:

  • Only the sealed unit needs replacing, not the entire window frame
  • A new double glazed unit restores full energy efficiency
  • Professional installation ensures proper sealing and fitting
  • New units come with warranties for peace of mind
  • Costs typically range from £60-£200 per unit, depending on size

DIY Solutions: Worth the Risk?

While there are DIY “solutions” available, such as drilling holes and using moisture-absorbing products, these are generally not recommended because:

  • They void any existing warranties
  • They provide only temporary relief
  • They can cause further damage to the unit
  • They don’t restore the window’s energy efficiency
  • They may lead to higher replacement costs later

When to Consider Full Window Replacement

Sometimes, replacing the entire window unit makes more sense than just the glass unit, particularly when:

  • Your window frames show signs of deterioration
  • The windows are over 20 years old
  • You want to upgrade to more energy efficient glass
  • Multiple units have failed in the same window
  • The frame’s integrity is compromised

Environmental Impact Considerations

Modern energy rated aluminium and glass units offer significant environmental benefits:

  • Better insulation reduces your carbon footprint
  • New units can improve your home’s energy efficiency by up to 30%
  • Many components are recyclable
  • Upgraded units qualify for energy efficiency certifications
  • Lower energy bills mean reduced fossil fuel consumption

Cost Comparison

Here’s a practical breakdown of your options:

  1. Professional unit replacement:
    • £60-£200 per unit
    • 20+ year lifespan
    • Warranty protection
    • Restored energy efficiency
  2. DIY repairs:
    • £20-£50 for materials
    • 6-12 month temporary fix
    • No warranty
    • Reduced effectiveness
  3. Full window replacement:
    • £300-£1000 per window
    • New frame and unit
    • Extended warranty
    • Maximum energy efficiency

Prevention: Protecting Your Investment

Maintaining your double glazed windows properly can significantly extend their lifespan and protect your investment. The key to prevention lies in regular maintenance and early intervention. Start by cleaning your windows with pH-neutral cleaners, avoiding harsh chemicals that can deteriorate window seals over time. Pay special attention to your window frames, ensuring drainage channels remain clear of debris that could trap moisture.

Proper ventilation throughout your home plays a crucial role in preventing blown double glazing. By maintaining adequate airflow, you reduce the stress on your window seals caused by extreme temperature differences and excess moisture. Consider using trickle vents or opening windows briefly each day, particularly in high-moisture areas like kitchens and bathrooms.

Making the Right Choice: Repair or Replace?

If you’re facing issues with your double glazing, making the right decision now can save you significant costs in the future. Consider your windows’ age – if they’re approaching the 15-year mark, investing in replacement units often proves more economical than repairs. Modern energy efficient glass options can dramatically improve your home’s insulation while reducing your heating bills.

Don’t let blown double glazing continue to affect your home’s comfort and efficiency. Our expert team at Swallow Glazing specialises in assessing and resolving double glazing issues quickly and effectively. Contact us today for a free, no-obligation assessment of your windows. We’ll help you understand your options and choose the most cost-effective solution for your home.

Frequently Asked Questions

The cost of fixing blown double glazing typically ranges from £60-£200 per unit. The final price depends on your window size, type of glass, and whether you need multiple units replaced. For an accurate quote specific to your situation, contact our team for a free assessment.

Unfortunately, blown double glazing won't fix itself. Once the seal has failed and moisture has entered between the panes, the only effective long-term solution is to replace the double glazed unit. Temporary DIY fixes might mask the problem but won't restore the window's energy efficiency.

While blown double glazing isn't immediately dangerous, ignoring the problem can lead to several issues. Persistent moisture between the panes can encourage mold growth, reduce your home's energy efficiency, and potentially compromise your window's security. It's best to address the problem promptly to avoid these complications.

Most standard home insurance policies don't cover blown double glazing as it's considered general wear and tear. However, if the seal failure was caused by accidental damage or extreme weather events, your policy might cover the replacement. Check your policy details or contact your insurer for clarification.

The most common signs include misting or condensation between the glass panes that can't be wiped away, a cloudy or foggy appearance that worsens with temperature changes, and visible water droplets trapped between the panes. You might also notice increased noise from outside and higher heating bills.

Quality replacement double glazed units typically last 15-20 years when properly installed and maintained. However, their lifespan can be extended through regular maintenance, proper cleaning, and ensuring good ventilation throughout your home. Modern units often come with warranties that provide peace of mind for your investment.