Question · VELUX Windows
How Long Do VELUX Windows Last?
The short answer
A well-fitted VELUX roof window can serve for decades, but there is no fixed date, because the frame, the seals, the flashing and the glass each age at their own pace. The sealed glass unit is usually the first part to show age. When the frame or its weather seals fail as well, the sensible step is a whole new unit.
Four parts, four lifespans
A roof window is an assembly, and it ages as one only when the parts are matched. Looking at them separately gives a better picture than any single number.
| Part | What wears it |
|---|---|
| Sealed glass unit | Edge seal breaks down, so the gap between the panes mists. |
| Frame and sash | Weather, sun and condensation on the inner face. |
| Weather seals | Rubber and gasket lose their spring over the years. |
| Flashing | Roof covering movement and the way it was fitted. |
The glass is the part people notice first, because a misted pane is plain to see. The flashing is the part that matters most, because it keeps the rain out around the edges, and it relies on the original fitting.
Before deciding anything, work out which part you are actually looking at. Replacement is a decision about one failing component or the whole unit, never about the age on the label alone. A cloudy pane and a stained lining are different problems, and they point to different jobs. The first is a glass question, and the second is a flashing or frame question.
What shortens the life
A few conditions make a window age faster. A south-facing slope with hot sun on a dark frame ages the finish quicker than a north-facing one. A bathroom or kitchen roof window sees steam daily, and unvented moisture sits on the inner face of the frame. Coastal air on the Severn side and exposed slopes towards the Cotswolds add wind and salt to the list.
Fitting matters more than any of that. A flashing kit that does not match the roof covering, or a frame that is packed out unevenly, lets water find the joint. Our VELUX window installation page describes how we fit and finish, and the guarantee on our workmanship runs for ten years.
Signs it is time to replace
- Misting between the panes. The sealed unit has failed. Condensation that you can wipe off the inside face is a different matter; that is room moisture, not a failed seal.
- A sash that sticks or sags. Hinges and the opening mechanism have worn, or the frame has moved.
- Cold draughts at the edge. The seals no longer close tight.
- Stains on the lining. Water is getting past the flashing or the frame.
- Peeling or rotting timber. The finish has failed, and the frame beneath it is next.
If only the glass has failed and the frame is sound, replacing just the sealed unit is generally not notifiable and is the lighter option. If the frame or flashing is also tired, a whole new unit is the better route, and that is notifiable building work. We handle the Building Control notification, and our misted and failed rooflights page explains the choices.
What a new one should bring
Modern roof windows have a better insulating value than units fitted a generation ago. In an existing home, Part L requires a replacement roof window to meet 1.4 W/m²K or Window Energy Rating Band B, so a new unit will usually be warmer at the glass than the old one.
It is also the moment to think about opening. Many older roof windows are fixed or open only by a bar at the bottom. A replacement can be a top-hung sash, a unit with a vent bar for overnight air, or an electric model whose rain sensor shuts the sash as the weather turns. Our page on VELUX INTEGRA explains the electric range. If a ladder is needed to reach the handle, the motor is worth pricing.
Making a window last
A little attention goes a long way. Clean the glass and wipe condensation from the frame so the finish does not sit wet. Keep the vent bar open in rooms that steam, which helps the air to move. Clear leaves from the slope above the window so water runs past it rather than pooling. On a roof with moss, a gentle brush down the slope keeps the flashing clear.
It also helps to open the sash fully once a season and look at the hinges and the seal. A rubber gasket that has flattened or cracked is the early sign that the sash will not close tight, and spotting it gives you time to plan a replacement rather than being forced into one in bad weather. Photograph the label on the frame while you are up there, so the size and type are on file when you come to order. Note the date of fitting as well, so you can see how the window has aged against its neighbours. If you have several roof windows, compare them: the one on the sunniest slope will usually show wear first, and it tells you what to expect from the rest.
When the time does come, swapping like for like is simpler if the size is known, and the VELUX size codes page shows where to find the label on the frame. For what the swap costs, see VELUX window fitting cost.
Ageing roof windows
Can I replace just the glass in an old VELUX frame?
Yes, when the frame, sash and flashing are all sound. Only the sealed unit is swapped, which generally is not notifiable building work. If the frame is tired too, a new whole unit is the better choice.
Does an old roof window need replacing before it leaks?
Not necessarily. Stains on the lining, a sagging sash or a seal that no longer closes are the signs to act on. A survey will show whether the frame and flashing are still sound.
Tell us about the room
A few details is all we need. We'll come out, advise and give you a written quote.
No pressure, no obligation.