Double Glazing Cost Per Window: UK Price Guide

Double glazing salespeople have a reputation — pushy, inflated “today only” discounts, quotes that mysteriously halve when you hesitate. It’s no wonder homeowners feel nervous asking how much does double glazing cost per window. The truth is refreshingly straightforward once you strip away the sales patter: most standard windows cost £400–£800 fitted, and anyone quoting you £1,500 per window is having a laugh. Here’s what you should actually pay.

The real prices: what windows actually cost

For a standard uPVC casement window (the white-framed, side-opening windows on most UK homes), fitted including VAT:

• Small window (600x900mm, e.g. bathroom): £350–£550
• Standard window (1200x1200mm): £450–£750
• Large window (1800x1200mm): £650–£1,000
• Bay window (3-section): £1,200–£2,500
• Full house (8–10 windows, 3-bed semi): £4,000–£7,000

Those are fair prices from reputable local firms. The national chains (you know the names) will quote 30–50% more as an opening gambit, then “discount” down to roughly these figures. It’s theatre. Get the local quote first and you’ll know exactly where you stand.

How much does double glazing cost per window in other materials?

uPVC is the default for a reason — cheap, durable, maintenance-free. But it’s not the only option:

• uPVC: The baseline above. Lasts 20–30 years. White is cheapest; woodgrain foils and colours (anthracite grey is everywhere now) add 10–20%.
• Aluminium: £800–£1,500 per standard window. Slimmer frames, more glass, very modern look. Excellent for contemporary extensions and bifold doors. Costs roughly double uPVC.
• Timber: £900–£1,800 per standard window. Beautiful, suits period properties, but needs repainting every 5–8 years. In conservation areas you may have no choice — draught-proofing original sash windows is often the smarter move for period homes.
• Composite (alu-clad timber): £1,000–£2,000. Timber inside, aluminium outside — the best of both, at a price to match.

What actually drives the price up or down?

• Number of windows: The per-window price drops significantly with quantity. One window might be £600; ten windows might average £450 each. Scaffolding, travel and setup are fixed costs spread across the job.
• Opening style: Fixed panes are cheapest; tilt-and-turn and fully reversible windows cost more than standard casements.
• Glass specification: Standard double glazing (4-20-4, argon-filled, low-E coating) is included in the prices above. Triple glazing adds 15–25%. Acoustic glass for noisy roads adds £80–£150 per window — worth every penny if you’re on a main road.
• Location: London and the South East run 15–25% above the national average. The North and Scotland are cheapest.
• Access: Upper-floor windows needing scaffolding or specialist access add cost. Mention it when getting quotes.
• Old window removal and making good: Should be included, but check — some cowboys quote low then add “extras” for removing the old frames.

How to buy without getting ripped off

1. Get at least 3 quotes — ideally from FENSA or CERTASS registered installers (this is important: it means the installation is certified as complying with building regulations, which you need when you sell).
2. Ignore the “discount”. If the quote starts at £12,000 and drops to £6,000 when you frown, the real price was always £6,000. Judge the final number, not the theatre.
3. Never sign on the day. Any company that pressures you to sign immediately is telling you everything about how they operate. A good firm is happy for you to think.
4. Check the guarantee. 10 years is standard on frames and installation. Get it in writing, and check whether it’s insurance-backed (so it survives if the company folds).
5. Ask about the energy rating. A-rated as standard now; A+ and A++ available. The difference in real-world bills between A and A+ is small — don’t pay a big premium for it.
6. Cooling-off period: You have 14 days to cancel anything signed at home under consumer law. Use it if you have second thoughts.

Which? has solid advice on buying double glazing including trader approval schemes — worth reading before you invite anyone round.

Is it worth it? The honest maths

Let’s be real: double glazing rarely pays for itself in energy savings alone. Replacing single glazing with modern double glazing on a typical 3-bed semi saves maybe £100–£180 a year on heating. On a £5,500 installation, that’s a 30+ year payback — longer than the windows last.

So why do it? Because the value isn’t just in bills:

• Comfort: No more cold draughts pooling by the windows, no more winter condensation streaming down the glass.
• Noise: Proper double glazing cuts traffic noise dramatically — life-changing on a busy road.
• Security: Modern multi-point locking vs a 1980s latch. Enough said.
• Saleability: Estate agents consistently say new windows help sell houses, even if they don’t add pound-for-pound value.
• Maintenance: No more annual sanding and painting of rotten timber frames.

Buy double glazing for comfort, quiet and security — with energy savings as a bonus, not the justification.

Secondary glazing: the cheaper alternative

If full replacement is out of budget — or you live in a listed building or conservation area where uPVC is forbidden — secondary glazing deserves a serious look. A discreet second pane fitted inside your existing windows costs £300–£600 per window installed, cuts noise dramatically (often better than double glazing for traffic noise), and noticeably reduces draughts and heat loss. It won’t match modern double glazing thermally, but it’s a fraction of the price and usually doesn’t need planning permission. For period properties with original sash windows, it’s often the right answer rather than just the cheap one: you keep the original glass and joinery, which matters for both character and value. Magnetic DIY kits start around £100 per window if you’re handy — a genuine weekend job.

The practical takeaway

Budget £450–£750 per standard uPVC window fitted, or £4,000–£7,000 for a full house. Get three quotes from FENSA-registered local firms, ignore the fake discounts, never sign on the day, and make sure the guarantee is insurance-backed. And if your existing timber windows are fundamentally sound, get a quote for professional draught-proofing and overhaul first — at £200–£400 per window, it’s a fraction of replacement and often all a period property needs.