Double glazing that does its job - high security, high energy efficiency

Old Double Glazing Vs New: Signs Your Windows Need Replacing

25th September 2020

uPVC double glazing offers remarkable longevity, with well-installed windows lasting between 10 and 20 years.

But eventually, they will need to be replaced, particularly if they are reaching the end of their life cycle.

If your windows are getting on in years, or if you’ve bought a house and you’re not sure how old the windows are, you may be considering getting them replaced. But how do you know it’s time for new windows? Here are some of the things you should be looking for. 

Visibly damaged frames 

uPVC windows are pretty robust and designed to withstand the elements, but over time, prolonged exposure to extreme weather will cause the frames to warp.

In some cases, this may be visible to the naked eye or evident through the window being more difficult to open and close. It’s a good indicator that your frames need to be replaced as warped frames will cause draughts to enter your home and reduce the thermal efficiency of your windows. 


Condensation on the inside of your windows, between the two panes of glass, is a sign that the unit has failed and needs to be replaced.

Condensation forms when warm air meets the cold glass, condensing and forming moisture. If this is happening between the window-panes, it means the unit is no longer air tight and will not be performing as well as it should.

But condensation on the actual glass from the inside is normal and shows that the window is doing its job properly. It’s only of a concern when the condensation is between the panes, inside the window itself.


If you can feel draughts within your home, you should really look at either repairing or replacing your windows.

Draughts occur when the seal between the frame and glass is damaged and will negatively impact your heating bills, while also preventing your home from warming effectively.

Draughty windows can be fixed in the short term with rubber foam insulating strips. However, if your windows are getting on in years, you should probably look into replacements. 

Increased heating bills 

If you’ve noticed a sudden, unexplained spike in your heating bills, your windows may well be the culprit.

Even if you can’t feel a draught in your home, your double-glazing may still be allowing the warm air to escape.

To locate hidden draughts, light a candle and hold it around the edges of your window frames. Where there is a draught, the flame will flicker. 


Leaks are further evidence that your windows are damaged and need to be replaced.Leaks can cause damage to your soft furnishings as well as items within the surrounding area of the window; leaky windows should be repaired or replaced as swiftly as possible to prevent expensive damage to your property. If you have come to the conclusion that your home needs replacement windows, or if you need further advice, request a callback from a member of our team.