Have you noticed your double-glazed windows looking slightly dull or perhaps felt a faint draught that did not used to be there? These small signs might seem harmless at first, but they can often point to the early stages of failed window seals. When caught in time, these issues can be repaired easily, preventing the appearance of misting and saving you from costly replacements later.
At RPS Double Glazing Repairs, we help homeowners across Dorset, Poole, Bournemouth and Ferndown detect seal failures before the problem becomes more serious. Understanding how to spot the signs early can make a huge difference in maintaining your home’s comfort, energy efficiency and value.
In this guide, we explain exactly why seals fail, what to look out for and how professional window repairs can restore your glazing to perfect condition.
Every double-glazed window depends on an airtight seal that keeps the insulating gas trapped between the panes of glass. When these seals start to deteriorate, the gas begins to escape, allowing moisture and cold air to seep in.
There are several reasons this happens. One of the most common causes is temperature fluctuation. Over time, constant expansion and contraction caused by hot and cold weather can cause the sealant to weaken and lose its elasticity. Poor installation can also contribute to early seal failure, as even the smallest misalignment or pressure during fitting can compromise the integrity of the window.
Ageing materials are another factor. Sealants naturally degrade over time, particularly if they were not of the highest quality when installed. Sunlight exposure can also accelerate deterioration, as ultraviolet light breaks down the compounds in the sealant.
Before misting appears, you may notice subtle signs such as a slightly cooler area around the window, or minor condensation forming at the edges of the glass. These early clues indicate that the insulating layer is beginning to fail.
The good news is that you do not have to wait for your windows to mist up completely to know something is wrong. There are a number of early warning signs that suggest your seals might be failing.
Look for cloudy edges around the glass where condensation begins to form. This often starts small but gradually spreads across the surface. You may also feel cold patches or draughts when standing near the window, even when it is closed.
If the reflection in your window glass seems slightly warped or distorted, that can also point to internal damage caused by moisture entering between the panes. In some cases, you might even spot tiny droplets of water inside the unit, confirming that the seal has broken.
These subtle signs should not be ignored. Addressing them early can prevent the need for a full window replacement and allow for simple uPVC window repairs or seal resealing.
While professional inspection is always recommended, there are a few simple checks you can carry out yourself to see if your seals might be failing.
Start by running your hand carefully around the edges of the frame. If you feel a draught or detect moisture, it could mean that air is entering where it should not. Next, try holding a lighter or a small candle near the edge of the glass. If the flame flickers, this indicates that air is leaking through a compromised seal.
You can also look closely at the swiggle strip, which is the thin metallic spacer between the two panes of glass. It should appear uniform in shape and colour. If it looks warped, corroded or discoloured, it is a strong indicator that the seal is no longer airtight.
Finally, check the external caulking around your window frame. Cracks or gaps in the sealant allow water to enter, which can lead to further damage. These simple tests can give you a good indication of whether your windows may need professional attention.
A failed window seal does more than just spoil the appearance of your glazing. It can have a serious effect on your home’s comfort and energy efficiency. When the insulating gas between the panes escapes, your windows lose their ability to retain heat.
This results in greater heat loss during winter, meaning your heating system must work harder to maintain a comfortable temperature. You might also notice increased condensation indoors, particularly on colder mornings, as warm moist air meets the now-cooler glass surface.
Over time, this not only affects comfort but also leads to higher energy bills and potential issues with damp or mould. Your home may feel less soundproof too, as the insulating barrier that blocks outside noise has been compromised.
That is why window repair should always be carried out promptly when a seal begins to fail. It is a simple step that can significantly improve your home’s warmth and efficiency.
Although you can identify some of the early signs yourself, repairing or replacing seals is a specialist job best left to professionals. A trained technician can inspect your double glazing using the right tools and determine whether the seal can be repaired or if the glass unit itself needs replacing.
The team at RPS Double Glazing Repairs provides a full range of expert services across Dorset, Poole, Bournemouth and Ferndown, including:
Misted double glazing repairs
Replacement double glazed units
uPVC window repairs
Double glazing repairs in Bournemouth, Poole and Ferndown
Our specialists use professional-grade materials to reseal or replace units, ensuring that your windows are restored to full performance without unnecessary cost. In many cases, only the glass unit needs replacement, not the entire frame, which can save you a significant amount of money.
What causes double glazing seals to fail?
Temperature changes, poor installation, ageing sealants and UV exposure are the most common causes. Over time, these factors cause the seals to lose elasticity and crack, allowing moisture to enter.
Can failed seals be repaired or do I need new windows?
In most situations, only the glass unit needs replacing rather than the entire window frame. This makes the repair faster and far more affordable.
How long does it take to fix misted windows?
Most misted double glazing repairs can be completed within a few hours, depending on the size and number of windows involved.
What is a swiggle strip?
The swiggle strip is the metallic spacer between the panes of glass. It helps keep the panes apart and maintain the air gap. If it appears bent, discoloured or damaged, it often means the seal has failed.
Do you cover the whole of Dorset?
Yes. RPS Double Glazing Repairs proudly serves Dorset, Poole, Bournemouth and Ferndown, offering fast, reliable and affordable local repair services.
Do not wait until your windows are completely misted or inefficient. Detecting and repairing failed seals early can save you money, reduce your energy bills and keep your home comfortable throughout the year.
Contact RPS Double Glazing Repairs today for friendly advice and professional window repair services across Dorset, Poole, Bournemouth and Ferndown.
You can also learn more about our replacement double glazed units and misted double glazing repairs by visiting our website or giving our team a call.