The Big Question Every UK Homeowner Eventually Asks
You've spotted misting between the panes, the handles are stiffer than they should be, the bedroom feels draughtier each winter. Within a week or two, a salesperson is on your doorstep quoting £8,000 to "rip the lot out and start again". But is that really what your home needs?
In our 30+ years repairing windows across Essex and East London, the honest answer is: roughly 9 in 10 homes don't need full replacement. The frames are sound, the hardware is repairable, the only thing that's failed is the glass unit itself - which is the cheapest part of the entire window to swap.
5 Questions That Decide It For You
- Are the frames structurally sound? Press firmly along the frame. Solid uPVC or aluminium with no cracks, bowing or rot points to repair.
- Do the windows still open and close? Stiff handles are usually a £40 hardware fix, not a frame fault.
- Is the only real problem the glass? Misting, cracks, cloudy units - all repairable without touching the frame.
- Are you staying for 2+ years? If so, repair pays back many times over. If you're selling within months, see the section on resale below.
- Do you actually want to change the style? If you're set on bay windows, sash conversions or aluminium upgrades, full replacement may be the only option.
Score 4 or 5 yes answers and repair is almost certainly your best route.
When Repair Is Clearly the Right Choice
If your frames are sound, repair wins on every measurable criterion:
- Cost: Sealed unit replacement is 40-60% less than full window replacement
- Speed: Under an hour per window vs 2-4 hours per full replacement
- Disruption: No scaffolding, no redecorating, no skip on the drive
- Waste: Sound frames stay out of landfill - far better for your carbon footprint
- Performance: Modern argon + Low-E units match brand-new windows watt-for-watt
- Guarantee: A reputable repairer offers a 25-year guarantee on the new unit
When Full Replacement Genuinely Makes Sense
There are scenarios where replacement is the right call - we'll tell you so honestly:
- Timber frames with significant rot, or uPVC frames that are warped, yellowed or cracked
- You're upgrading from single glazing (no sealed unit to replace)
- You're changing style - bay to flush, casement to sash, top hung to tilt-and-turn
- Building Regulations require upgraded specs - typically on extensions or change of use
- Frames are 35+ years old and you're planning to stay 20+ years
2026 Cost Comparison: 3-Bed Semi With 8 Windows
| Option | Typical 2026 cost | Time on site | Disruption |
|---|---|---|---|
| Sealed unit replacement (all 8) | £900 - £1,400 | Half a day | Minimal |
| Hardware refresh (handles, hinges, gaskets) | £300 - £600 | 2-3 hours | None |
| Full uPVC replacement | £5,000 - £9,000 | 2-3 days | Significant |
| Full aluminium replacement | £8,000 - £14,000 | 3-4 days | Significant |
A potential saving of £3,500 - £8,000 for the same end result: clear glass, warm rooms, working windows.
What About Resale Value?
Many homeowners replace before selling assuming it'll add value. The data is less generous: full replacement typically returns 50-75% of its cost at sale. Sealed unit replacement, by contrast, almost always returns more than it costs because buyers see clear, working windows without thinking about it - and a poor EPC rating drags any sale price down.
We dig deeper into this in our guide to windows and home value.
The Honest Bottom Line
Get a quote for both. Any reputable repairer (us included) will be straight with you about which one your windows actually need. Across our Essex and East London service area, around 90% of the homes we visit only need repair - and they save thousands as a result.