# When to replace windows | TrustedGlazing Source: https://trustedglazing.co.uk/guides/when-to-replace-windows Home / Guides / When to replace windows Living with them · 15 of 19 # When is it actually time to replace your windows? Replace when the frames themselves have failed: timber that has gone soft, uPVC that has distorted or cracked, or a system whose hinges and mechanisms are no longer made. Misted glass, a broken handle, a dropped sash and a draughty seal are all repairs, and each costs a small fraction of a replacement window. Almost everything that makes a window annoying to live with can be fixed without replacing it. The question is whether the frame is still sound, because that is the part you cannot repair. Guide 15 / 19 Series Living with them Issued 12 Oct 2026 Revised 14 Oct 2026 Applies to England and Wales Reading 3 min · 593 words Contents - 01The test: is the frame sound? - 02What is a repair, not a replacement - 03The honest case for replacing anyway - 04Questions 01 / 04 ## The test: is the frame sound? Everything else bolted to a window is a serviceable part. The frame is not, so that is the only thing worth assessing first. - **Timber.** Press a screwdriver into the bottom corners of the cill and the bottom rail. If it sinks in, the wood has gone and that section needs splicing or replacing. If it is firm, the window has decades left in it. - **uPVC.** Look along the frame from one end. A bowed outer frame, a sash that no longer sits square in its opening, or cracking at the welded corners means the profile has given up. Discoloration on its own does not. - **Aluminium.** The frame almost never fails. What fails is the thermal break in older systems and the finish, and neither is a structural problem. If the frame is sound, you are looking at a repair, whatever the symptom is. In one line Replace when the frame itself has failed. A blown unit, a stiff handle or a draughty gasket are repairs, and they cost a fraction of a new window. ## What is a repair, not a replacement These are all serviceable, and an installer who tells you otherwise is selling rather than diagnosing: - **Misted or blown double glazing.** The sealed unit is a separate component that slides out of the frame. See misted double glazing. - **A handle, hinge or locking mechanism that has failed.** Parts, not products. See window hardware. - **A draught around the opening sash.** Usually a perished gasket or an adjustment. See draughty windows. - **A cracked pane.** The glass comes out and a new one goes in. See replacement glass. ## The honest case for replacing anyway There are three situations where replacing a window that still works is a reasonable decision rather than a sold one. - **Single glazing.** No repair turns a single-glazed window into a double-glazed one, and nothing else you can do to a house loses heat at the same rate. - **Obsolete systems.** If the hinges and mechanism are no longer manufactured, every future repair becomes a scavenging exercise. This is common on systems fitted before the late nineties. - **Doing the whole house at once.** The survey and the setting up are shared across every opening, so replacing eight windows together costs noticeably less per window than replacing them one at a time over eight years. That is a reason not to drip-feed a replacement you have already decided on. It is not a reason to start. What is not a good reason: a salesperson telling you that your windows are "past their guarantee", which describes a piece of paper rather than a window. ## Questions How long should windows last? A well-made uPVC window is generally expected to last a couple of decades or more, timber indefinitely if it is maintained, and aluminium longer still. Any specific number you are quoted is a marketing figure rather than a measurement, so judge the window in front of you rather than its age. My windows are twenty years old. Do they need replacing? Not because of their age. Check the frame using the test above. Twenty-year-old frames in sound condition with failed sealed units are a glass job, not a window job. Will new windows pay for themselves in energy savings? Replacing single glazing makes a difference you will feel. Replacing working double glazing with newer double glazing generally does not pay back within the life of the window, and anyone presenting it as an investment is selling. Comfort and noise are better reasons than arithmetic. Note This guide is general information about England and Wales, not advice about your specific property. TrustedGlazing is an introducer and does not install, survey or quote. Rely on your installer's survey and your local authority for decisions about your own home. One installer, not five ## When you are ready for a price Tell us your postcode and what you need. If we have a local installer covering you, your enquiry goes to one of them, and nobody else. Check my postcode Previous · 14 Guarantees explained Next · 16 Draughty windows Same series ## More on living with them All guides - 16 · Living with them ### Why your windows are draughty, and what actually fixes it A draught from a window is nearly always one of four things: a perished rubber gasket, hinges and a locking mechanism that have stopped pulling the sash up tight, a gap between the frame and the wall hidden behind the plaster or render, or a trickle vent doing exactly what it was fitted to do. 3 min read 3 questions answered Read it - 17 · Living with them ### Which windows actually reduce noise? Secondary glazing reduces noise more than replacement double or triple glazing, because what blocks sound is a wide air gap and a secondary pane sits 100mm or more behind the original rather than the 16mm or 20mm inside a sealed unit. 3 min read 3 questions answered Read it - 18 · Living with them ### What makes a window or door actually secure? Two things to put in writing: PAS 24 for the window or doorset as a whole, and a TS007 3-star cylinder, or a 1-star cylinder paired with 2-star handles. 3 min read 3 questions answered Read it