Faulty Double Glazing Should You Replace A Whole Window?

Faulty double glazing: Do I have to replace the whole window?

It’s a common misconception amongst homeowners that when your window’s double glazing fails, it’s necessary to replace the whole unit, including the frame. But this isn’t always the case. 

If the frame is still in good condition, calling a glazier to replace the sealed glass only is a time and cost-efficient solution to faulty double glazing. 

The type and extent of the damage will decide whether the whole unit, including the frame, will need to be replaced or just the glass. 

What is double glazing? 

Double-glazed windows consist of two panes of glass, separated by a spacer to create an air gap which is filled with insulating gas. 

They offer superior energy efficiency. So much so, that in 2002, building regulations were set that all replacement windows must be at least double-glazed C rated. The only exceptions to this, are when the property is listed or in a conservation area. 

Their efficiency relies on being securely sealed. If this sealing is damaged the window fails to perform properly, and so must be replaced. 

Why do people think the frame must be replaced when the double glazing fails?

Because the tight seals are such a crucial part of the double-glazing engineering, many people believe that the frame and glass panes are inseparable. But just replacing the glass panes and keeping the original frames does the job most of the time. 

However, if a professional recommends a full replacement, it’s worth investing in one. These are usually only recommended when there is structural damage to the frames or multiple components are deteriorating. 

When does the whole window need replacing? 

The frame is damaged 

A damaged frame affects the window’s performance and security. Newly replaced glazing won’t last long in damaged frames. If the timber is warped, uPVC is cracked or the aluminium is corroded, a whole new window unit is required. 

The window no longer meets modern standards 

To reduce heat loss in homes, building regulations require windows and doors to meet a required level of energy efficiency. U-Levels are an example of this. 

In England and Wales, the minimum required U-value for already-existing homes is 1.4 W/m²K. Older windows may not be able to meet these requirements or may be beyond repair. 

Multiple window components have failed 

When your window’s, hinges, locks and glazing are all showing signs of wear, it’s more efficient to replace the entire window, rather than focusing on individual components. 

Aesthetic update 

Maybe your windows don’t fit with your home’s exterior style anymore and you’re looking to implement an aesthetic update. This will obviously involve a complete frame replacement rather than just the glass panes. 

Signs your double glazing has failed: 

Your double glazing has probably failed if: 

• There’s condensation between the panes of glass.
• The glass is always misty, and the mist cannot be wiped away.
• There’s visible cracks or damage.
• Draughts are getting into your home, around the glass.
• Your home is losing heat or is less energy efficient.
• Outside noise is louder than usual.

If any of these signs seem familiar, your double glazing is likely deteriorating and in need of replacement. 

For more information on failed double glazing, check out our previous blog, How Can I Tell If My Double Glazing Needs Replacing?

Is repairing misty glass an option? 

Once condensation has started to mist the glass from inside the sealed panes, the glass cannot be restored back to its original state. This means replacing the glass is the only effective option here. 

While there are de-misting services available, these are temporary solutions. Replacing the glass makes sure your home is energy efficient and has a well-kept appearance.  

When can the glass only be replaced? 

Even if the glass is damaged, the entire unit may not need to be replaced. In most cases you can avoid paying out for a new frame, and just replacing the glass panes when: 

• The glass is cracked or shattered.
• The seals have failed, resulting in misted glass.
• Condensation has become trapped between the panes.
• Chipped glass risks the insulation remaining effective. 
• Upgrading to more energy-efficient glass. 

Typically, if the frame remains structurally sound and intact, only replacing the glazing can restore the window’s appearance and fix any inefficiencies without having to replace the entire window. This saves time, money and keeps your home’s exterior aesthetically consistent. 

Is replacing the glazing less expensive? 

For most scenarios, replacing the sealed double-glazing is less expensive than an entire window, including the frame, as:

• The frames are already in place. 
• Less time is spent on installation. 
• Less material is required. 
• Finishes on the exterior and interior of your home are left unaffected. 

Glass-only replacement is the less expensive option when dealing with failed seals and glass damage. 

Final thoughts 

Damaged glazing doesn’t always mean a full replacement. If the window frames are in good condition, replacing only the sealed glass is usually quicker and more cost-effective.  

However, when the frames are damaged, outdated or faulty, a full window replacement is necessary to make sure your home stays energy efficient and completely secure. 

We specialise in glass replacement, so if you’re considering replacing your window’s glass we can help. We’ll assess your window fixtures and advise you on the most appropriate solution. 

Whether you’re looking to replace your glazing or just need some professional advice, our team of glazing experts are here to help. Call us for a quote today!