Double glazing provides our homes with exceptional thermal efficiency all year round, keeping us warm in the winter and cool in the summer. Double glazing allows you to use less energy throughout the year. With energy prices sky high and still rising, it’s vital to make sure that your home is as energy-efficient as possible. If you invest in double glazing, you’ll be on your way to protecting your home against heat leaking out, and spending more than you need to on heating bills.

Unfortunately, double glazing is not infallible, and it does have a shelf life. Once it has failed, you will struggle to maintain the right levels of thermal efficiency in your home. Therefore it is incredibly important to understand what failed double glazing looks like, and spot when your double glazing is faulty or blown so that you can address it quickly.

How does Double Glazing become ‘blown?’

Double glazing becomes blown when there is a leak somewhere in the window that allows the insulating gas, an inert gas like argon, to escape, allowing moisture and air to filter in. Double glazing condensation between the two window panes in the window frame is the most obvious sign. This generally occurs through the seal, which is the piece of black rubber that runs around the edge of the glass. As this is the weakest part of the window, this tends to be where breaks can happen. The first you might know about it is when the glass is not clear, known as misted double glazing (the condensation inside we just mentioned).

Several factors cause blown double glazing, and these include:

  • Poor installation: If the windows have not been installed correctly, the seal may fail prematurely.
  • Age: Over time, the seal can deteriorate because of exposure to the elements and just general wear and tear.
  • Damage: Impact from objects, extreme weather situations, or structural problems with your own home can cause the seal to break.

You’ll know that your double glazing has blown if the glass appears cloudy and you can see vapour but you can’t wipe it off. Essentially, the condensation is on the inside of the glass between the two panes which is why you can’t remove it. The only way that water vapour from outside gets into a double glazing unit is through a leak because the entire window unit is vacuum sealed with thermal insulating gas between the glass panes ordinarily.

Other symptoms of blown double glazed windows include:

  • Draughts: If you can feel draughts inside your home even when the windows are closed, then there is a breach somewhere in one or more of your window seals.
  • Increased energy costs: Higher electricity payments can indicate that your windows are not performing as well as they have done in the past. The window seals can be damaged and vulnerable even without the classic presentation of misted double glazed windows.

The Importance Of Prompt Repairs

It’s important to address blown windows as quickly as possible in order to:

  • Maintain your home’s energy efficiency and keep your energy consumption and heating bills as low as possible
  • Prevent further damage to the window unit
  • Avoid the growth of mould and mildew because of condensation

Once the unit has blown, you will need to get it fixed or replaced as soon as possible so that you can keep your home warm and energy efficient. Seal failure will lead to condensation between the panes and misted double glazing eventually causes condensation inside your home which poses health risks.

How To Fix Blown Double Glazing

When it comes to dealing with blown double glazing, you’ve got a few options:

Which Is The Best Option?

Replacing the seal yourself is by far the cheapest option and certainly the one that can be done quickest. Replacing the seal is one of the easier double glazing repairs and pretty straightforward for a DIY enthusiast. There are lots of guides on the internet to show you how to do it. You’ll need a few bits of equipment and a certain amount of know-how to ensure that you don’t break the glass or any other part of the unit during the replacement.

Having the seal replaced by a professional is another possibility, it’s cheaper than replacing the whole unit and probably a safer option if you don’t really do much DIY. A professional will also be able to vacuum out the air between the two panes of glass so that you have a vacuum between them instead of moisture-filled air. It’s not as effective as the original insulating gas that the unit came with, but if you want to ensure that you won’t have another condensation build-up for a while, then this will help.

Whilst replacing the entire window might seem somewhat dramatic, it’s probably the best option. Once double glazing blows, you’ve lost all of the argon gas that sits between the two panes of glass. Even if you do choose to replace the seal, you’re still going to have lost essential insulating properties from the inside of your double glazed window.

If you’d like to compare prices for double glazing installers, you can do it right here on our website!

How To Repair The Seal On Misted Double Glazed Windows

Replacing the seal yourself is the cheapest option if you’re faced with a blown window. You’ll need to assemble a few tools and take good care of the unit to make sure you don’t unintentionally damage the glass. There are a few other pitfalls you’ll need to take care to avoid and these include:

  • Accidentally breaking the glass panes
  • Failing to obtain an airtight and watertight hermetic seal
  • Voiding any current warranties for your double glazing

If you make a decision to update the seal yourself, here are the steps to follow:

  • Remove the old seal carefully using a putty knife or scraper with a flat blade
  • Clean the location thoroughly to remove any remaining residue
  • Apply the brand new seal to a dry surface with smooth, even strokes
  • Allow the seal to dry completely before replacing the window

Professional Seal Replacement On A Blown Window

Having the seal replaced by an expert is one option if you don’t have older windows and avoids the cost of replacement double glazed units. An expert can remove the air between the window panes using a vacuum which will help prevent condensation from building up again inside the unit. If they can replace the argon gas in the double glazed unit then they will before installing a new seal, but this can be tricky.

What Are The Benefits Of Replacing A Double Glazed Unit?

Window replacement is always the best option. Blown glazing can be an indicator that the unit has reached the end of its life. Replacement costs will be higher than window repair, but at least you’ll know you have optimal energy efficiency for your home. Use our online tool to compare costs from different double glazing installers.

Replacing misted windows rather than repairing them offers several advantages:

  • A new sealed unit offers optimal thermal performance
  • It’s a long-lasting solution so you won’t have to worry about misty windows again
  • You’ll have access to new glass products and technology (e.g., low-E coatings, triple glazing etc) for improved insulation and appearance
  • The new windows come with a warranty for complete peace of mind

What Factors Should You Consider When Deciding Between Repair And Replacement?

There’s a few things to think about before you make a decision, these include:

  • The age of your windows and their remaining lifespan
  • How bad the damage is and whether repair will offer a lasting solution
  • The difference between repair or replacement costs, the lifespan of each option, and value for money
  • The appearance of your windows

Comparing Costs And Deciding On An Expert Installer

The cost of repairing or replacing blown double glazing varies depending on specific factors including:

  • The size and number of affected windows
  • The type of glass and sealing material
  • The complexity of the job
  • Costs in your local area

When you’re looking for an installation company, make sure you check out their reviews and references from past customers. Choose a firm with an established track record that offers clear quotes with transparent pricing. The glazing products should be as energy efficient as possible and come with a warranty. You can fill out our form with your requirements and you’ll receive quotes from local installers that we’ve vetted for you.

Fixing blown double glazing will lower your heating costs and remove unpleasant draughts and temperature fluctuations. If you replace all the windows then your home will increase in value, and you’ll have the satisfaction of knowing that you have also reduced your carbon footprint. Enjoy all the benefits of a well-insulated home and save on energy prices.

Fixing Blown Double Glazing: Frequently Asked Questions

Can I prevent my double glazing from blowing? 

There isn’t a huge amount you can do to prevent double glazing from blowing because it is often associated with the age of the windows or damage caused by a specific weather event. However, there are certain things you can do to limit the risk. Cleaning and inspecting the window seals regularly can spot issues before they become serious problems. Always repair any cracks or damage to the glass as soon as possible, and avoid the use of harsh cleaners and abrasive products as this can cause window seals to deteriorate.

Should I change one blown double glazing unit, or update them all? 

This decision depends on several factors such as the age of your windows, their condition, and how much you want to spend. If only one window has blown then replacing just that one unit may be the best cost-effective solution. However, if your windows are old and showing signs of wear, then it will be cheaper in the long run to replace them all.

How long does it take to replace a blown double glazing unit? 

The time required to replace a blown double glazing unit varies depending on the size of the window, its accessibility, and the complexity of the set up. In most cases, a professional installer can replace a single unit within a couple of hours. However, if you have custom-sized windows or are replacing more than one unit, then the process will take longer.

Does fixing blown double glazing actually make a difference to my energy bills? 

Yes! Blown double glazing units allow the warm air to escape and cold air in, so you’ll be relying more on your heating system to keep your home at the right temperature. Window replacement guarantees your property’s insulation, reducing draughts, and minimising heat loss for a comfortable home and lower energy bills.

How do I select a professional double glazing installer? 

When choosing a double glazing installer, look for a company with significant and demonstrable experience in repairs and replacements, supported by testimonials from previous satisfied customers. Pricing should be clear and transparent with no hidden costs. Always make sure that the installer offers warranties or guarantees on their window. Don’t hesitate to obtain multiple quotes as this will help you to compare services and find the best quality installer in your local area. Use our form for the best results.