Windows are easy to ignore until something goes wrong. A draught you can’t quite place. A patch of damp on the frame. A handle that’s started to stick. None of it feels urgent on its own, so it gets put off. The trouble is that tired windows quietly cost you money every month. In a typical home, around 18% of heat loss goes straight out through the glazing and frames, so windows that have stopped performing show up on your energy bill long before they fall apart.
The good news is that not every fault means a full replacement. Some are a quick repair. We’ve fitted and repaired windows around Wolverhampton, Willenhall and Walsall for over 20 years, so below are the seven signs worth paying attention to, how to check each one yourself, and further down, when you can probably hold off.
1. You can feel a draught with the windows shut
A breeze coming through a closed window is the clearest sign the seals have gone. Pick a windy day, shut everything, and run the back of your hand slowly around the edges of the frame and where the opening sash meets it. If you feel cold air moving, the gaskets have perished or the sash has dropped out of line.
A draught does more than make a room uncomfortable. Cold air coming in means warm air going out, so your heating works harder to keep up.
2. Misting or fog between the panes
This one gets confused all the time, so it’s worth being clear. Condensation on the inside surface of the glass, the side you can wipe, is usually a ventilation issue rather than a window fault. Misting trapped between the two panes is different. You can’t wipe it away because it’s sealed inside the unit, and it means the seal has failed and the insulating gas has escaped.
Once a sealed unit has gone, it’s no longer insulating properly. The glass can often be replaced on its own without changing the whole window, which we cover below.
3. Rot, damp or crumbling frames
Old timber frames suffer when water gets in and stays. Press gently along the frame, especially at the bottom corners where rain collects. If the wood feels soft or spongy, or you can push into it, rot has set in and it will spread. On older uPVC, look for cracking, yellowing, or sections that have gone brittle. Frames in this state can’t be sealed reliably and tend to keep letting in water and cold.
4. They stick, jam, or won’t lock properly
Windows should open, close and lock without a fight. If you’re forcing a handle or a sash, the cause is either worn hinges and gaskets, which can be repaired, or a frame that’s warped or dropped, which usually can’t. A window that no longer locks cleanly is also a security weak point, and it’s the kind of fault burglars look for. Worth dealing with rather than living around.
5. Your heating bills have crept up
If your bills have climbed without your habits changing, ageing windows are a common culprit. A lot of the older terraces and semis around the Black Country still have early double glazing fitted in the 80s or 90s, and those units lose far more heat than a modern equivalent. Single glazing and early double glazing have much higher U-values, the measure of how quickly heat escapes. Older single glazing can sit above 4.0 W/m²K, while a modern energy-efficient window can get down to around 0.8. That’s a big difference in how much warmth stays in the room.
The Energy Saving Trust estimates that replacing single glazing with A-rated double glazing saves around £140 a year on energy bills for a typical home. For more on the numbers, our double glazing cost guide breaks down what you can expect to pay and recover.
6. Outside noise is getting through
Stand by the window with everything closed. If you can clearly hear traffic, voices or next door’s garden, your glazing isn’t insulating against sound the way a modern unit would. This matters most if you’re near a main road or a busy junction. Newer units, and acoustic glass in particular, make a noticeable difference to how quiet a room feels.
7. Water getting in, or visible cracks and damage
Cracked or chipped glass, a window that no longer sits square in its opening, or water pooling on the sill after rain all point to a window at the end of its life. Damage like this hits security and insulation at the same time, and water that keeps getting in will eventually reach the wall and plaster behind it.
When you might not need to replace at all
Plenty of window companies will tell you to replace the lot regardless. We’d rather you spent your money where it actually helps, so here’s the honest version.
Some faults are a straightforward repair. Worn handles, hinges and locking mechanisms can usually be swapped out. Perished rubber gaskets can be replaced to stop a draught. A single misted sealed unit can often be reglazed on its own, keeping the existing frame, for a fraction of the cost of a full window. And condensation on the inside surface of the glass is almost always a ventilation issue, sorted by using trickle vents, improving airflow and managing moisture in the room, not by buying new windows.
It’s usually worth replacing when the frames themselves have failed, when several windows are affected at once, or when old single glazing is costing you more in lost heat than the repairs would save. If you’re not sure which camp you’re in, that’s exactly what a proper survey will tell you.
What to look for if you do replace
A few things are worth knowing before you buy.
Check the Window Energy Rating. Windows are rated by the British Fenestration Rating Council on a scale from A++ down to G, covering the whole window rather than just the glass. Higher is better. Alongside that, ask for the U-value, where lower means better insulation.
On frame material, the right answer depends on the property and the look you want, rather than there being one best option. uPVC gives strong insulation for the price and is the most common choice. Aluminium offers slimmer sightlines and more glass for the same opening, which suits a contemporary look. We go into more detail in our guide to uPVC, aluminium and timber frames.
Finally, replacement windows have to meet building regulations. Use an installer registered with a competent person scheme such as Certass or FENSA and the certification is handled for you. If you live in a conservation area or a listed building, check with your local council first, as there may be restrictions on what you can fit.
Frequently asked questions
How long do double glazed windows last?
The frames of a well-made modern window last a long time, but the sealed glass units have a shorter life and can start to fail after roughly twenty years, sometimes sooner on older installations. Misting between the panes is the usual sign a unit has reached that point.
Is condensation between the panes always a sign I need new windows?
Not the whole window. Misting between the panes means that sealed unit has failed, but the glass can often be replaced on its own while keeping the existing frame, as long as the frame is still sound.
Can I replace just the glass instead of the whole window?
Often, yes. If the frame, hinges and locks are in good condition and only the sealed unit has failed, reglazing is a much cheaper fix than a full replacement.
Do I need building regulations approval to replace windows?
Yes, replacement windows have to comply with building regulations. The simplest route is to use a Certass or FENSA-registered installer, who registers the work for you. Otherwise you’d need to arrange building control approval yourself.
How much can new windows save on energy bills?
The Energy Saving Trust puts the saving at around £140 a year for a typical home moving from single glazing to A-rated double glazing. The exact figure depends on your property, your current windows, and how many you replace.
Not sure where your windows stand?
If you’ve spotted one or two of these signs and want a straight answer on whether to repair or replace, we can take a look. We’re a family-run firm fitting windows and doors across Wolverhampton, Walsall, Willenhall, Bilston, Dudley, Kingswinford, Wordsley, Stourbridge and Kidderminster. Get an instant online quote or get in touch for a no-obligation survey.
