Last updated 27 April 2026
Cost of Sash Windows London 2026
Sash window prices by type
Fitted prices for vertical sliding sash windows across London as of Q2 2026, including VAT, frame, glazing, fitting, disposal of old frames and FENSA self-certification. These are real per-window ranges we quote weekly — heritage sash specialists and timber joiners typically quote 10-30% higher; national chains quote 2-3x higher.
| Sash type | System / spec | Low | High |
|---|---|---|---|
| uPVC Heritage | |||
| uPVC heritage sash | APX Heritage / Liniar Sash | £1,200 | £2,400 |
| uPVC sash with run-through horns | APX Heritage | £1,400 | £2,500 |
| uPVC sash with Georgian bars | APX Heritage | £1,500 | £2,700 |
| Timber softwood | |||
| Engineered redwood / pine sash | Spiral balance | £1,800 | £3,800 |
| Engineered softwood with weights | Traditional weights and pulleys | £2,200 | £4,200 |
| Accoya softwood (50yr warranty) | Spiral balance | £2,300 | £4,200 |
| Timber hardwood | |||
| Sapele / oak hardwood sash | Spiral balance | £2,500 | £4,500 |
| Hardwood with weights and pulleys | Traditional cast-iron weights | £2,800 | £5,000 |
| Retrofit | |||
| Slim double-glazed retrofit (existing frame) | Slimlite / Histoglass 12-14mm | £900 | £1,400 |
| Sash refurbishment + slim retrofit | Existing frame restored | £1,400 | £2,200 |
uPVC vs timber sash — long-term cost
Upfront cost versus 50-year lifecycle cost. Timber wins on authenticity, uPVC wins on upfront cost and zero-maintenance. Lifetime cost lands roughly equivalent — but only if timber is properly maintained.
| Spec | Upfront | Lifespan | 50-yr total |
|---|---|---|---|
| uPVC heritage sash (APX Heritage) | £1,800 | 25–30 years | ~£3,600 (1 replacement) |
| Timber softwood sash, painted every 8-10 years | £3,000 | 50+ years | ~£3,800 (5 paint cycles) |
| Timber hardwood sash (sapele/oak) | £3,800 | 60–80 years | ~£4,300 (4 paint cycles) |
| Accoya softwood sash | £3,200 | 50+ years | ~£3,900 (3 paint cycles) |
| Original frame + slim retrofit glazing | £1,200 | 30+ years (glass), original frame indefinite | ~£2,400 (1 reglaze) |
Conservation area context
London is dense with sash window stock — most Victorian and Edwardian terraces in Richmond, Twickenham, Chiswick, Hampstead, Islington and Clapham have original sash windows. Conservation area rules vary by council and Article 4 direction:
| Area | Front elevation | Rear elevation |
|---|---|---|
| Strawberry Hill TW1 (Richmond Council) | Timber sash only — LBC for listed | Timber preferred, uPVC heritage by application |
| Bedford Park W4 (Hounslow / Ealing) | Timber sash with sightlines matching original | Timber or uPVC heritage with horns and bars |
| Richmond Green (Richmond Council) | Timber sash, weights and pulleys | Timber or uPVC heritage |
| Hampstead NW3 (Camden) | Timber sash, period-correct profiles | Timber preferred |
| Chiswick W4 (Hounslow) | Timber on listed buildings; uPVC heritage often approved on non-listed | uPVC heritage usually approved |
| Islington N1/N7 (Islington Council) | Timber sash with run-through horns | Timber preferred |
What drives the price
Six factors do most of the work between the low and high ends of every range. If you're comparing three quotes, make sure they all spec these the same way.
1. Run-through horns +£100–£300
Traditional Victorian-style horns extending below the meeting rail are usually authentic-required for conservation. Genuine run-through horns (machined into the sash) cost more than applied/stuck-on horns.
2. Weights & pulleys vs spiral balances +£200–£500
Cast-iron weights and brass pulleys are period-correct, smoother in operation, and serviceable indefinitely. Spiral balances are concealed, slightly cheaper, but stiffen up over 15-20 years and are harder to repair.
3. Astragal / Georgian bars +£100–£400
True bar (glass divided into smaller panes) is most authentic and most expensive. Applied bar (single pane with bars stuck on inside and outside) is mid-cost and visually close. Internal-only or external-only bars are cheapest.
4. Original glass restoration +£150–£400
Original Victorian crown and cylinder glass has subtle ripples and bullion patterning. We carefully remove, store and re-bed it during refurbishment — usually back into the upper sash where it's most visible.
5. Glazing spec +0–25%
Slim retrofit double glazing (12-14mm Slimlite/Histoglass) is conservation-approved and 1.6-1.9 W/m²K. Standard 28mm modern double glazing won't fit slim sash rebates. Acoustic laminated glass adds 10-15%.
6. Listed building consent +£400–£900
Grade II listed buildings need LBC. Drawings, heritage statement and council fees typically £400-£900. Lead time 8-16 weeks. Always engage early — quote for design fees separately from installation.
What's included
Every fitted sash window quote from Apex Glazing includes:
| Free site survey, timber/condition assessment and conservation feasibility check |
| Frame and sashes (uPVC, softwood, hardwood or Accoya as specified) |
| Double-glazed sealed units (slim retrofit 12-14mm or modern 28mm depending on spec) |
| Run-through horns and astragal Georgian bars where requested |
| Weights and pulleys or spiral balances (your choice) |
| Brass or chrome ironmongery (sash lifts, locks, fasteners) |
| Full draught-seal pile, parting bead and staff bead |
| Removal and disposal of old frames, or refurbishment of original where retained |
| FENSA self-certification (Reg 40373) — registered with your local authority |
| 10-year guarantee on frames, 5 years on sealed units |
Frequently asked about sash window cost
How much do sash windows cost in London in 2026?
Fitted sash windows in London in 2026: uPVC heritage sash £1,200–£2,400 per window; timber softwood sash £1,800–£3,800; timber hardwood sash £2,500–£4,500; slim retrofit double-glazed unit (existing frame) £900–£1,400. Prices include VAT, frame, glazing, fitting, disposal of old frames and FENSA self-certification.
uPVC sash vs timber sash — which is cheaper long-term?
Over 50 years, well-maintained timber sash works out roughly equivalent in total cost to uPVC, despite costing 50-80% more upfront. uPVC sash has a 25-30 year lifespan and then needs full replacement. Timber softwood sash, repainted every 8-10 years, lasts 50+ years. Hardwood (oak, sapele) lasts 60-80 years. uPVC wins on upfront cost and zero-maintenance; timber wins on lifecycle cost and authenticity.
Are uPVC sash windows allowed in conservation areas?
It depends on the council and Article 4 direction. Some London conservation areas (Bedford Park W4, Strawberry Hill TW1, parts of Richmond TW9, Hampstead NW3) require timber-only sash on front elevations. Rear-elevation uPVC heritage sash with run-through horns and astragal bars is more often approved. Always check with the local planning officer before ordering — Apex Glazing handles pre-application enquiries as part of the survey.
What is slim retrofit double glazing?
Slim retrofit double glazing replaces the single-pane glass in your existing original sash frame with a slim 12-14mm sealed unit. It costs £900–£1,400 per sash (vs £1,800-£3,800 for full timber replacement). It keeps the original frame, weights, pulleys and putty detail — important for listed and conservation buildings. U-value drops from ~5.0 (single glass) to 1.6-1.9 W/m²K. Apex installs Slimlite Histoglass and Pilkington SG specs.
What is APX Heritage uPVC sash?
APX Heritage is our UK-fabricated uPVC vertical sliding sash system designed to mimic Victorian and Georgian timber sash. It includes traditional run-through horns, deep bottom rail, astragal Georgian bars (true bar or applied), Heritage White, Cream or Black colour options, and 1.4 W/m²K whole-window U-value. Fitted price £1,200–£2,400 per window. Often approved at the rear of conservation properties.
Do sash windows still use weights and pulleys?
Original timber sash windows in London (Victorian and earlier) use cast-iron weights in cavities behind the frame, balanced over brass pulleys with sash cord. Modern timber sash replacements offer either weights-and-pulleys (period-correct, more expensive, smoother) or spiral balances (concealed, slightly cheaper, slightly stiffer). uPVC sash uses spiral balances or modern block-and-tackle. Apex restores original weight systems where requested.
Can original sash window glass be saved?
Yes. Original Victorian and Georgian crown glass and cylinder glass have a slight ripple and bullion patterning that modern float glass doesn't. We carefully remove and store original glass during sash refurbishment, then re-bed it back in the upper sash (where it's most visible) with new putty. Slim retrofit doubling can sometimes incorporate original glass on one face. Survey is needed to confirm condition and feasibility.
How much does timber hardwood sash cost vs softwood?
Hardwood sash (oak, sapele, accoya) costs £2,500–£4,500 per window fitted; softwood (engineered redwood, Scandinavian pine) costs £1,800–£3,800. Hardwood lasts 60-80 years vs softwood's 40-50. Hardwood holds paint better, resists rot more, and is the spec for premium projects. Accoya softwood is treated for 50+ year warranty and runs about 15-20% above standard softwood.
What's included in an Apex sash window quote?
Every fitted sash window quote from Apex Glazing includes: free site survey, timber/condition assessment, frame and sashes, double-glazed sealed units (slim retrofit or modern 28mm), traditional run-through horns and astragal bars where requested, weights and pulleys or spiral balances, brass or chrome ironmongery, removal and disposal of old frames, full draught seal, FENSA self-certification (Reg 40373), and a 10-year guarantee on frames.
