This is a very popular question in the world of double glazing, and there are a few factors to consider when replacing window panes. In general though, the answer is yes, and it’s known as a pocket window replacement.

All double glazed units are sealed separately. For example, when a French door has two window panes, but only one shows visible mist and water, that is the single pane that will require replacement – not the whole door.

It’s a common misconception that a window split into four sections is a single window. If you can see four panes, those four panes will be individual and can be replaced as necessary.

For double glazed windows and doors, the frames do not need replacing if cosmetic repairs like cloudy or misty panes, breakages or cracks are required. Existing frames can be restored after replacing the affected glass.

Why do double glazed units fail?

Double glazed units are air filled and held together by a hot-melt sealant. This energy efficient design helps to improve thermal insulation, sound-proofing and safety. More often, the part of the window that typically causes this failure is the spacer between the panes.

When this starts to wear or crack, the unit will begin to fail. Condensation will then builds up between the panes of glass, and this is what causes the misted window effect.

Rarely is it the frames that causes a double glazed units to fail. Even in the case of older windows and doors that have functioned well for 30+ years, individual panes can still be replaced. Indeed, any age or make of window can benefit greatly from an individual pane replacement.

Why Do Double Glazed Unit Fail - Blown Window - Misty Glaze

Will they meet current safety requirements?

In years gone by there were fewer rules and regulations on window glass size and thickness. As a result, many older patio door glass units are unsuitable for 4mm toughened glass and (in a lot of cases) the 6mm toughened glass required to meet current safety requirements and the latest energy standards that can help to lower household bills.

Can you replace individual panes in timber frames?

In the case of older, timber-style windows and doors the condition of frames will need careful consideration before a decision is made regarding replacing window panes. In some cases, beads and parts will have become rotten and moving parts like hinges, locks and handles might not be in the best condition. Glass pane replacements in timber-style frames are also a lot more labour intensive than uPVC and Aluminium. So, it’s likely that such an individual replacement would cost considerably more than modern double-glazed windows.

When opting for glass replacement within older wooden frames, it’s important to be aware of any aftercare required that can include sanding down and painting beads and window frames. After the timber beads have been released there may be damage to the existing paint. There is also the chance old beads will split, depending on what condition they’re in and how they were fitted previously.

Replacement Double Glazing - Timber Windows - Misty Glaze

Treating problems individually is the most cost-effective way of replacing window panes and it’s most certainly cheaper than replacing the whole frame. However, there are some older glazing systems (such as certain types of aluminium patio doors) that are also very labour intensive and as a result can be more costly.

What’s the best long-term option?

Where frames are very old, the fixings that hold the frame around the glass can be damaged or rusty. Attempting to replace an older frame around new glass can mean that doors never work the same again and the locks, wheels and runners that are attached to them can become problematic. It is always best to get some estimates for completely brand new doors or windows if you feel this may be an issue. Additionally, brand new doors and windows will most likely be installed with a 10-year warranty and will be hassle-free to operate, so they may well be the better and more sensible long-term option.

It’s also important to remember that even if you think you’re saving money by just replacing window panes in old frames, you may end up paying the price if those frames finally deteriorate and need replacing well before your replacement glass panes do.

Like a well-manicured front lawn or a brand new three-piece suite, stylish windows are one of the key components that help to make up a beautiful-looking home that you can be proud of. If yours are made from more modern uPVC or aluminium it is certainly worth gathering some estimates for replacing just the faulty window panes rather than facing the burden of costly frame replacements. And now that you know you can simply replace each failed unit at a very low cost, you can be sure your windows will look great and stand the test of time.