UPVC Sash Windows Cost

What UPVC sash windows cost to supply and fit in 2026, how prices vary by size and mechanism, and whether they save money versus timber over 25 years.

Last reviewed: 2026-07-20 • 7 min read • Verified against 6 contractor quotes

UPVC Sash Window Prices by Size

UPVC sash window costs vary by opening size. Prices below are supply and fit from FENSA-registered installers (January 2026 quotes from Checkatrade and MyBuilder).

Installation costs £220-£280 per window including removing the old sash, fitting the new UPVC unit, making good the reveals, and disposal of the old window. Two-storey properties add scaffold costs (£400-£800 for a full house, divided across all windows).

Mechanical vs Spring Balance Systems

UPVC sash windows use two balance mechanisms. This affects cost and lifespan.

Spring Balances (Standard)

Cheaper UPVC sash windows use spiral spring balances hidden in the frame sides. A steel spiral spring tensions when you raise the sash, holding it open. Cost: £600-£950 installed for standard sizes.

Spring balances work well for the first 10-15 years. After that, the springs weaken and the sash drops when opened. Replacing the springs costs £80-£150 per window in parts and labour, but many installers refuse the work on old UPVC frames (non-standard spring sizes, difficult access). At that point you're replacing the whole window.

Mechanical Balances (Premium)

Higher-end UPVC sash windows use constant-force balances (a steel tape wound around a drum, similar to a tape measure). Brands: Rehau Heritage, Deceuninck, Residence Collection. Cost: £800-£1,400 installed (15-20% more than spring balances).

Mechanical balances last 25-30 years and can be serviced without removing the sash. The tape can be replaced if it eventually fatigues. These systems also achieve slimmer sightlines (18-22mm vs 25-30mm for spring balances), looking closer to timber originals.

For a 6-window Victorian terrace, mechanical balances cost £900 more upfront (£5,400 vs £4,500) but avoid a £1,200-£1,800 re-balance or replacement job at year 15. Net saving: £300-£900 over 25 years, plus better aesthetics.

UPVC vs Timber: 25-Year Cost Comparison

UPVC sash windows cost less to buy and maintain than timber. Here's the full lifetime cost for a single window over 25 years.

For a 10-window house, UPVC saves £16,400 over 25 years versus timber softwood sash. Timber hardwood (oak, accoya) costs even more: £2,000-£2,500 per window initially, and lasts 50+ years but still needs repainting every 7-10 years.

The trade-off: timber sash windows can be repaired indefinitely (replace a rotten sill, splice in new timber), while UPVC is throw-away at end of life. If you plan to keep the property 40+ years, timber may be cheaper long-term. For 20-30 year ownership, UPVC wins on cost.

What Affects UPVC Sash Window Prices

Glazing Type

Standard UPVC sash windows come with 24mm double glazing (4mm glass / 16mm argon gap / 4mm glass). This is included in the prices above. Upgrades:

• Low-E coated glass: +£30-£50 per window (reflects heat back into room, saves 10-15% on heating)
• Acoustic glass: +£80-£120 per window (6mm laminated outer pane, reduces traffic noise by 3-5dB extra)
• Triple glazing: +£150-£220 per window (overkill for sash windows; the extra weight stresses the balances)

Colour and Finish

White UPVC is the base price. Other finishes cost more:

• Woodgrain foil (rosewood, oak, mahogany): +£80-£140 per window
• Anthracite grey / black: +£60-£100 per window
• Dual colour (white inside, woodgrain outside): +£120-£180 per window

Woodgrain foils fade in direct sun after 12-18 years, especially south-facing windows. Black and anthracite UPVC absorb more heat and can warp slightly (1-2mm frame bow) on large sashes. Stick to white UPVC for longevity, or choose timber if colour matters.

Georgian Bars

Georgian astragal bars (the grid pattern) cost +£40-£70 per window for bars bonded to the glass surface. True divided lights (individual small panes) aren't available in UPVC sash windows because the UPVC frame can't be made thin enough.

Most period property owners avoid Georgian bars on UPVC sash windows. They look fake (the bars are 8-10mm thick plastic stuck to the glass). If you want Georgian 6-over-6 sashes, you need timber.

Security Hardware

UPVC sash windows meeting PAS 24 security standard (required for insurance on new builds) include multi-point locking and anti-lift devices as standard. Upgrading to:

• Sash horns (decorative corner projections): +£15-£25 per window
• Traditional sash fastener (Brighton pattern): +£20-£35 per window (instead of modern cam lock)
• Key-lockable sash stops: +£30 per window (prevents opening beyond 100mm ventilation gap)

Planning Restrictions on UPVC Sash Windows

Before ordering UPVC sash windows, check if you need planning permission. Rules vary by property type.

Conservation Areas

If your property is in a conservation area, replacing timber sash windows with UPVC on any elevation visible from the street usually requires planning permission. Many councils reject UPVC applications in conservation areas.

Check your local council's conservation area guidance. Some allow UPVC on rear elevations only. Call the planning department before paying a deposit.

Listed Buildings

Listed buildings (Grade I, II*, II) require listed building consent to replace windows. UPVC is almost always refused on listed buildings. You'll need like-for-like timber sash windows with slim double glazing or secondary glazing instead.

Article 4 Directions

Some streets have Article 4 directions removing permitted development rights for window replacement. This means even non-listed houses need planning permission to change window materials. Check your council's planning portal or call to ask.

How Long Do UPVC Sash Windows Last?

UPVC sash windows last 20-35 years depending on quality and exposure. The UPVC frame profile itself lasts 35+ years (it doesn't rot or need painting). What fails first:

• Balances: Springs weaken after 15-20 years, mechanical balances last 25-30 years
• Gaskets: Rubber seals perish after 18-25 years, causing draughts (replaceable but labour-intensive)
• Locks: Cam locks and espag mechanisms fail after 20-30 years (replaceable, £40-£80 per window)
• Glass seals: Argon leaks from the double glazing after 20-30 years, causing condensation between panes (requires new glass units, £120-£200 per window)

After 25 years, you're typically looking at £300-£500 per window to refurbish (new balances, gaskets, and glass units), or £700-£1,000 to replace with new UPVC sashes. At that point, most people replace.

Compare to timber sash windows: the timber frame lasts 80+ years if maintained. You replace rotten sills (£200-£400), re-cord the sashes (£120-£180), and repaint every 5-7 years. Total refurb cost every 25 years: £600-£900 per window, but the original frame stays.

Are UPVC Sash Windows Worth It?

UPVC sash windows make sense if:

• You're staying in the property 15-30 years (long enough to recoup the cost, short enough to avoid major refurb)
• The property is not listed or in a conservation area (or rear elevation only)
• You want low maintenance (no repainting)
• Budget is tight (£4,500-£9,000 for a 6-window house vs £8,500-£13,000 for timber)

Stick to timber sash windows if:

• The property is listed or in a strict conservation area
• You want authentic period appearance (slim sightlines, true Georgian bars)
• You're restoring the house to original spec
• You plan to own the property 40+ years (timber beats UPVC on long-term cost if you can do your own painting)

Sources

Pricing verified against:

• Checkatrade UPVC sash window quotes (Jan 2026, 8 installers, London/Southeast)
• MyBuilder supply-and-fit quotes (Dec 2025–Jan 2026, FENSA-registered installers)
• Rehau Heritage sash window price list (trade, Jan 2026)
• Deceuninck Heritage 47 product spec and retail pricing guide
• Historic England guidance on UPVC in conservation areas (updated Oct 2025)
• GGF (Glass and Glazing Federation) UPVC window lifespan data (2024 survey)