Double glazed windows are far more repairable than most people realise. A misty or fogged-up window doesn't mean replacing the whole frame — just the glass unit. Draughts are usually a failed seal or misaligned frame. And hardware faults (handles, hinges, locks) are cheap to fix. Full window replacement only really makes sense when the frame itself has failed.
Average UK labour and parts costs — always get multiple quotes from local engineers.
UPVC window frames last 20–35 years. Timber frames, if properly maintained (painted every 5–7 years), can last 50+ years. The glass unit (the sealed double-glazed unit) typically lasts 15–25 years before the seal fails and misting begins. Importantly, frame failure and glass failure are independent — you don't need to replace both.
Window repairs are almost always more cost-effective than full replacement. A misted unit needs only the glass replacing (£80–£200), not the frame. Handle, hinge, and lock repairs are cheap and straightforward. Only replace the whole window if the frame is warped, rotted (timber), or otherwise structurally compromised.
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The three main window frame materials in UK homes are uPVC, timber, and aluminium — each with distinct repair and replacement considerations. uPVC is by far the most common, accounting for around 85% of UK window installations. It's low-maintenance and affordable to replace (£400–£800 per window), but frames that have discoloured or warped cannot be easily repaired. Timber frames are found in older and period properties and can last decades if regularly maintained with paint or stain every 5–7 years. Rotten sections can often be spliced and repaired rather than fully replaced — a much cheaper option. Aluminium frames are durable, slim, and increasingly popular in modern builds, but they're the most expensive to replace (£600–£1,200 per window). Knowing your frame type helps you understand what repairs are realistic.
Windows play a major role in your home's thermal efficiency, and their condition directly affects your EPC rating — important for both energy bills and property value. Replacing single glazing with modern double glazing can save £100–£200 per year on heating costs, according to the Energy Saving Trust. Under UK Building Regulations (Part L), replacement windows must meet minimum thermal standards (a U-value of 1.4 W/m²K or less for the whole window), which all modern double and triple glazed units achieve. Regular maintenance is minimal for uPVC (just cleaning and occasional hardware lubrication), but timber frames need repainting every 5–7 years at a cost of £30–£50 per window. Keeping on top of this prevents costly rot repairs later and helps maintain the window's insulating performance.
No — a misty or foggy double glazed window means the sealed unit has failed, not the frame. You only need to replace the glass unit (£80–£200 per pane), not the entire window. This is a common and affordable repair.
Window repairs vary widely. Glass unit replacement (misting) costs £80–£200. Handles and hinges cost £30–£80. Lock replacements run £60–£120. Full window replacement is £400–£800 per window and should only be needed if the frame itself has failed.
UPVC frames last 20–35 years. Double glazed sealed units typically last 15–25 years before seals fail and misting begins. The frame and glass unit can be replaced independently — you don't need to replace both just because one has failed.
Internal misting means the hermetic seal on the double glazed unit has broken, allowing moisture to enter the air gap. The frame itself is usually fine — just the glass unit needs replacing at £80–£200, not the whole window.
Repair cost estimates are UK averages sourced from Checkatrade, Which?, and MyBuilder. Prices include labour and VAT. Always get at least two quotes from qualified tradespeople before proceeding with any repair.
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