A uPVC window does not reach an expiry date and stop. The frame outlives every other part of the window, and the sealed glazing unit, the hardware, the gaskets and the surface finish each wear on their own shorter cycles. Ask which part has failed rather than how old the window is, because the answer decides whether you need a repair or a replacement.
Treating a window as one object with one lifespan is why people replace things they did not need to. Here is the same window, broken into the parts that fail on different schedules.
Read the right-hand column carefully, because it is the whole point. Four of the five failures are repairs. Only the first is a replacement.
Our own product guide sets the maintenance expectation this implies: inspect the glazing seals at least once a year, particularly at the bottom of the unit, and replace them if tears or cracks appear, along with the glazing beads at the same time. Lubricate hinges, handles, espagnolettes, roller bolts and locks at least annually. None of that extends the frame's life. All of it extends the working life of the window.
Expect several decades from the frame, and expect to have replaced other parts along the way. A well-fitted, maintained uPVC window is generally still doing its job at twenty years and often well beyond, while the sealed units and hardware inside it may be on their second life by then.
Three factors move that more than the brand on the label.
Installation quality. A frame fitted out of square never seals properly and wears its hardware unevenly from the first week. Our installation instructions require frames to be plumb, level and square with equal diagonals, and our warranty excludes units that are not, which tells you how much it matters.
Exposure. South and west-facing elevations take the most sun and weather, and our own maintenance guidance singles them out. Two identical windows on the same house will not age at the same rate.
Maintenance. Annual lubrication and clear drainage holes cost nothing and are the difference between hardware lasting and hardware seizing.
Worth naming the honest limit of any figure here: nobody can tell you how long your windows will last without knowing how they were fitted and how they have been treated.
No, and conflating the two is the most common misunderstanding on this topic.
A warranty is a commercial commitment covering manufacturing and material defects for a stated period. A lifespan is how long the product keeps working. They are different numbers measuring different things.
Our own cover is structured as separate periods for separate things rather than as one figure: the product, the surface treatment, and the glazing each carry their own term, and sealed units are guaranteed for a defined period against dust and condensation forming between the panes.
What a warranty tells you is where the manufacturer expects defects to show, not when the window will stop working. A window is not more likely to fail the day after cover ends.
Two exclusions worth knowing, because they surprise people. Condensation on the inside pane caused by insufficient ventilation is not a product defect, and neither is condensation forming on the outside pane of energy glass.
Both are covered in our draughty door and condensation guide from the ventilation side. And glass cracks are ordinarily an insurance matter rather than a warranty one.
You can date them yourself in a couple of minutes, which is more useful than guessing from the style.
Look at the spacer bar inside the sealed unit, the strip running around the edge of the glass between the panes. On units supplied through the glass industry guarantee scheme it carries a label with the fabrication month and year. Read it through the glass from inside.
The window itself also carries a label noting its date of manufacture. On our products that label is what a warranty claim is assessed against, and the customer is responsible for evidencing the delivery date if it is needed.
Why bother. Knowing the date separates two very different situations: a fifteen-year-old window with one misted unit, which wants a glass replacement, and a thirty-five-year-old window with failing frames and no available spare hardware, which wants replacing.
If neither label is legible, the glazing bead profile and the hardware style will let a fitter place it to within a few years.
Six signals genuinely point at replacement rather than repair.
Four things that look like replacement signals and are not:
A misted pane. The sealed unit has failed, not the window. Replacing the glass is a fraction of the work and cost of replacing the frame.
A draught. Adjust the window first, then check the gaskets. Our window adjustment guide covers the free fixes, and a perished gasket is a replaceable strip rather than a replaceable window.
A stiff or broken handle. The handle drives the locking mechanism. Handles are replaceable, and a stiff one is often just a dry espagnolette.
Discolouration. Yellowed or dulled uPVC is cosmetic. It affects nothing about how the window works, and no chemical whitening treatment improves the surface without damaging it.
That last group is where most unnecessary replacements start, and a fitter quoting for new windows has no reason to point it out.
