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Replace Your Double Glazed Unit - A Useful Guide

Author: Samuel Beckingham
Updated: Feb 05, 2024
7 minutes read
  • How you can get replacement double glazed units
  • A guide to replacing your glazing
  • Replacing misted double glazing

Double glazing can sometimes go wrong. Instead of paying out for a whole new window, you might be able to opt for replacement double glazed units instead. You can save yourself a lot of money by going through this option.

This article will explain how replacement double glazed units work. It will detail when you should replace the glazing and how much it costs. This useful guide will outline the steps you need to follow to replace double glazed units and advise why it’s important they’re working efficiently.

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Can You Replace Double Glazed Units?

Instead of getting new windows and frames, it’s possible that you may be able to get replacement double glazed units instead. If the materials of the frame are still intact and it’s only the glazing that’s failed, it could be more beneficial for you to simply replace the glass. As well as saving money, you can also save time.

The benefits of doing this affects the energy efficiency of the window. With two panes of glass and a working gas infill, double glazing in your window keeps more heat in your home than single glazing does. If any part of the window is compromised, this can end up costing you money. This is where replacement double glazed units come in.

When to Get Replacement Double Glazed Units

Mostly, double glazing is meant to last up to 35 years. Some units are so well made and in ideal conditions that they can last even longer. In the instances where the gas infill has leaked or the sealed unit has broken, this can present a problem. The heat won’t be regulated in your home as well as it should, which is not ideal in the winter. To get around poorly installed glazing, replacement double glazed units can help.

The tell-tale signs that your double glazing needs replacing are usually to do with the appearance of condensation, cloudy glass or the presence of draughts. Without the insulating layer of gas, the following issues can occur:

  • Condensation between the two panes

  • Cloudy glass

  • Damage to the glass (chips or cracks)

  • Draughts

Isometric Window Profile

If any seals have broken or been damaged, the insulating gas inside may leak out. You can usually tell if this is the case because condensation will be present on the inside panes of the glass, i.e., you can’t reach it to wipe it away. There is no temperature regulation without a gas infill, and if your windows aren’t in direct sunlight, condensation may not even appear and this can go unnoticed. Check if you need replacement double glazed units by seeing if the glass is much colder to the touch than it normally is.

Broken seals can also cause misted double glazing units. This is simply an effect of the condensation. These issues can be caused by damage to the panes, which could have let the infill escape. If chips or cracks are present and the window is performing well, keep an eye on it as it may get worse with time. If condensation starts to form, then you will need to consider getting replacement double glazed units.

Draughts can be a more symptomatic issue with the frame, but they can sometimes appear if the glass seal or the glazing has failed or is damaged. A small amount of background ventilation is to be expected from trickle vents, which is not a cause for concern. If, however, there is a noticeable change in the amount of cold air coming through your windows, then replacement double glazed units could solve this issue.

How Much Is It to Replace Double Glazed Units?

Replacement Glazing Vector

The cost of replacing misted windows can be anything from £30 to £500. It depends on how large your windows are as the time and labour involved will dictate the price you pay. The style of the window will also affect the price. As the frame material makes up the majority of the price of new windows, replacement double glazed units can offer you savings of up to 50%.

Checkatrade specifies that lower and higher price ranges can differ by about £50. A low price to pay for a standard double glazed bay window replacement can cost £225, whereas a high price would be £275. You can see the average cost of replacement double glazed units in the interactive graph below.

How to Replace Double Glazed Units

Most issues experienced with double glazing that’s failed often comes from the unit not being installed correctly in the first place. Unless you are competent in window installations, it’s best to leave this to the experts as any imperfections (no matter how small) can seriously affect how your windows perform. For general interest and those that are capable, here’s how to install replacement double glazed units.

Wedge Gasket

The first step is to remove the wedge gasket that’s inside the window frame. This stops the glazing from moving, but is also waterproof and airtight.

Glazing Beads

These are simply the decorative finish of the window frame. On the outside of the window, carefully remove these from the bottom to the top. You should also make note of where any glazing packers or spacers are located.

External Window Installation Isometric

Remove the Unit

Now that you can access the unit, you can remove it. It’s then ready for any replacement double glazed units to fit in place.

Replace and Fix

Keeping hold of the new unit, check the spacers and secure the glazing beads in the reverse order you removed them. Finally, secure the wedge gasket to lock the glazing into place.

The above is a general guideline for replacement double glazed units. It will not be applicable to all window types, but is suitable for the most common double glazing. Where underlying issues exist with the window frame, this is not the best method to choose. Timber frames, for example, are more susceptible to rot, which will worsen with time. Replacement double glazed units in timber frames may not perform any better.

Can You Fix Blown Windows?

Some companies can remove the condensation in your windows, which is even cheaper than buying replacement double glazed units. It works by having a hole drilled into the frame spacer bar and either drawing out the moisture or pumping in warm air to remove the existing condensation. Once done, the hole is then sealed and the unit put back in place.

The problem with fixing windows in this way is that any underlying issue is not solved, so condensation can reappear within six months. You’ll then have to pay for the same service again, which will end up costing you more consistently across the same time frame. If you opt for replacement double glazed units instead, any issues with the gas infill, cracks or breakages are then resolved. Bigger issues that require the frame to be fixed will require a full replacement.

How Does Double Glazing Affect My Home’s Efficiency?

Energy Saving Trust has done many studies on the costs and savings of double glazing. The most efficient grades of glass are A++ rated, which can save you up to £235 a year, if upgrading from single paned windows. If the units have failed, double glazing is no better off than single glazing, meaning you won’t have these savings if you don’t opt for replacement double glazed units.

Window Temperature Vector

As much as 10% of a home’s heat can be lost through its windows, and this could be even worse if they aren’t performing their best. When the gas infill has failed and condensation sets in, the internal and external temperatures aren’t optimised as efficiently as they should be. In winter, this is the most problematic as home heating will end up costing you more for set temperatures to be reached. Preventing this issue early with replacement double glazed units can help save you money.

Top Tips Before Replacing Glazing

The best way to ensure your replacement glazing will fit and do a better job than your existing setup is to measure it several times. The height and width will be important, but so will the thickness. If you are attempting to do the job yourself, you could end up with replacement double glazed units that your window frame can’t support.

You can always upgrade the type of glass you have at the same time. Remember that replacement double glazed units don’t have to be identical to your previous ones. Upgrading to Low-E glass can increase its thermal performance, which will save you even more money.

If you want to completely spruce up your windows, it may be a case of replacing the whole thing, including the frame. Replacement double glazed units won’t change the aesthetic of your home as the frame would remain the same. Changing from uPVC to timber or aluminium, for example, can only be done as a full replacement job.

Instead of searching for replacement double glazing units near me, simply click on the button below to receive quotes from local tradespeople in your area.

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