Should I repair or replace my windows?
What actually wears out on a uPVC, timber or aluminium window, which of those things is a cheap part rather than a new window, and the realistic lifespans to judge against.
- Difficulty
- beginner
- Time
- 25 min
- Read
- 4 min
Short answer
Hinges, stays, handles, gearboxes, gaskets and sealed units are all replaceable parts costing a fraction of a new window. Replace the window when the frame itself has failed — welds cracked, timber rotted beyond splicing, aluminium corroded — or when the frames are so far out of shape that no hardware will fit properly.
Replacement windows are sold on the basis that a window is a single product that wears out. In practice a window is a frame with hardware and glass in it, and the frame usually outlasts everything else by decades. Knowing which layer has failed is what stops a three-figure repair turning into a five-figure job.
Step by step
- Separate the frame from everything in it.The frame is the part that is expensive to replace. Hardware, seals and sealed units are all bolt-on components. Diagnose which layer has failed before getting a quote for anything.
- Assess a uPVC frame.Look at the welded corners for cracks, and at the frame for bowing, discoloration that will not clean off, and any softening. A sound uPVC frame with tired hardware is worth repairing every time. A frame with split welds or badly distorted sections is not.
- Assess a timber frame.Probe the bottom rail, the cill and the bottom of each stile with a bradawl. Localised rot is spliceable and a well-maintained timber window can be repaired almost indefinitely. Widespread failure across every member, particularly where the joints have opened, is a different matter.
- Assess an aluminium frame.Older aluminium windows are frequently sound structurally but have no thermal break, so they run cold and stream with condensation. The frame is not failing; its performance is. That is a replacement decision on comfort and energy rather than on condition.
- Price the parts before the window.A friction stay, a gearbox, a handle, a set of gaskets or a sealed unit are all modest amounts. Get a window repair specialist to quote for the repair alongside any replacement quote — many will, and it changes the picture.
- Use realistic lifespans as a sense check.Quality uPVC frames commonly last several decades, with hardware needing attention along the way and sealed units typically the first thing to go. Timber windows in a maintained house last a century or more. Sealed units are the shortest-lived component in any of them.
- Count the windows and the reasons.One failed window is a repair. Every window in the house failing at once usually means a whole installation of the same age reaching the end of its hardware life together, which is still a repair — but a big enough one that replacement is a fair comparison.
- Factor in what replacement brings that repair does not.Better thermal performance, better security hardware, trickle ventilation where the current windows have none, a new guarantee and building regulations compliance — or the Scottish equivalent — certified in writing. Those are real, and they are what makes replacement worth considering on a merely tired window.
- Factor in what repair keeps.Original timber windows in a period or listed property carry real value and, in a conservation area or on a listed building, replacing them may not be permitted at all. Check before assuming replacement is an option.
- Get three quotes and compare like with like.Frame material and system, glass specification, hardware, trickle vents, how the opening is made good, and who provides the building regulations certificate. Quotes for windows vary enormously and often are not comparing the same thing.
Alternatives
- Repair the hardware only: Hinges, stays, handles, gearboxes and gaskets. The right answer for a sound frame with tired mechanisms, and by far the cheapest option.
- Replace the sealed units only: For misted or blown units in a sound frame. Also the route to upgrading to laminated or better-performing glass without touching the frames.
- Replace the sashes, keep the frames: Offered by some suppliers on uPVC. Worth asking about where the outer frames are sound and the opening sashes have failed.
- Full replacement: New frames and sashes. The right answer for failed frames, and a fair choice where performance and security are the driver rather than condition.
- Secondary glazing: Adds thermal and acoustic performance without touching the existing windows. The usual answer in listed buildings and often the better one for noise.
Questions people ask
How long should uPVC windows last?
Quality frames commonly last several decades. The sealed units and the hardware will need attention well before the frames do, and treating those replacements as the window failing is the mistake that drives most premature replacements.
My windows are twenty years old. Should I replace them?
Age alone is not a reason. Assess the frame, then the hardware, then the glass. Twenty-year-old frames in good condition with a couple of failed units and stiff hinges are a repair job.
Does replacing windows add value?
It affects saleability more than value, and a badly matched replacement in a period house can reduce both. Judge it on comfort, running cost and condition rather than on an expected return.