Wooden sash windows cost more upfront than any other sash material, but the total cost of ownership depends on your maintenance commitment and energy targets.
Are you considering wooden sash windows for your home in 2026 and wondering how they compare on price and upkeep? The upfront cost is higher than other materials, but the long-term financial picture depends heavily on how you maintain them.
Wooden sash windows cost £1,200–£2,200 per 1.2m x 1.2m window in 2026, which is 40–60% more than uPVC. The long-term cost depends on repainting every 5–7 years at £150–£300 per window. Compare quotes from local installers to see timber vs uPVC costs.
- Wooden sash windows cost £1,200–£2,200 per 1.2m x 1.2m unit in 2026.
- Timber sashes are 40–60% pricier than uPVC and 15–30% more than aluminium.
- Repaint every 5–7 years at £150–£300 per window per repaint.
- Factory-finished engineered timber offers a 10-year paint cycle but costs 20–30% more.
- Meeting Building Regulations requires a whole-window U-value of 1.6 W/m²K or lower.
- Wooden sash windows cost more upfront than any other sash material, but the total cost of ownership depends on your maintenance commitment and energy targets.
- A standard timber sash window achieves a centre-pane U-value of 1.2–1.6 W/m²K, which meets current Building Regulations for replacement windows.
- The average annual energy saving from replacing single-glazed timber sashes with double-glazed timber sashes is £160–£220 for a typical semi-detached house.
- Quick numbers
- The main trade-off for timber sashes is maintenance frequency versus aesthetic and heritage value.
- You can verify a timber sash installer’s competence through MCS, TrustMark, and FENSA certification.
- Wooden sash windows are the most expensive sash option but the only one that can be repaired rather than replaced, which lowers lifetime cost.
A standard timber sliding sash window, measuring approximately 1.2 m x 1.2 m, typically costs between £1,200 and £2,200 for supply and installation in 2026 (Checkatrade 2026 cost tables). This is roughly 40–60% higher than an equivalent uPVC sash and 15–30% higher than an aluminium sash, according to Glass and Glazing Federation (GGF) 2026 market benchmarks (GGF, 2026).
The long-term cost advantage of timber depends on your maintenance commitment. You will need to repaint every 5–7 years, budgeting £150–£300 per window per repaint (Checkatrade 2026). Alternatively, you can choose a factory-finished engineered timber sash that claims a 10-year paint cycle, but this costs 20–30% more upfront. For listed buildings, replacement timber sashes must match the original profile, which can add 25–50% to the cost (Historic England, 2025).
A standard timber sash window achieves a centre-pane U-value of 1.2–1.6 W/m²K, which meets current Building Regulations for replacement windows.
Building Regulations Approved Document L (2021 edition, updated for 2025) requires replacement windows to achieve a whole-window U-value of no more than 1.6 W/m²K (gov.uk, 2025). Timber sashes with double glazing typically meet this standard.
A well-sealed timber sash with 4-16-4 argon-filled double glazing has a centre-pane U-value of approximately 1.2 W/m²K, comparable to a modern uPVC casement (Energy Saving Trust, 2026). Draught-proofing a single-glazed timber sash can reduce heat loss by up to 50%, but the window itself still falls short of the 1.6 limit unless the glazing is upgraded (Energy Saving Trust, 2026).
For listed or conservation-area homes where double glazing is not permitted, secondary glazing can be a solution. It costs £300–£600 per window and achieves a U-value of 1.8–2.2 W/m²K (Historic England, 2025).
The average annual energy saving from replacing single-glazed timber sashes with double-glazed timber sashes is £160–£220 for a typical semi-detached house.
This figure comes from the Energy Saving Trust’s 2026 “Replacement windows” savings table, based on a gas-heated semi-detached house with three sash windows replaced (Energy Saving Trust, 2026). The saving assumes the new windows are draught-stripped and have low-E glass. Without low-E coating, the saving drops by roughly 25%.
The payback period on the cost difference between timber and uPVC sashes is typically 25–35 years, so the decision to choose timber is rarely driven by energy savings alone (Energy Saving Trust, 2026).
Quick numbers
| Measure | Value | Source |
|---|---|---|
| Average cost per timber sash window (supply + install, 1.2 m x 1.2 m) | £1,200–£2,200 | GGF 2026 cost tables; Checkatrade 2026 |
| Typical centre-pane U-value (double-glazed, low-E, argon) | 1.2 W/m²K | EST 2026 |
| Annual energy saving (3 single-glazed → double-glazed timber sashes, semi-detached) | £160–£220 | EST 2026 |
| Repaint cost per window (every 5–7 years) | £150–£300 | Checkatrade 2026 |
| Secondary glazing cost per window (listed building solution) | £300–£600 | Historic England 2025 |
| MCS-certified timber sash installer count (UK, 2026) | ~180 | MCS Register search, May 2026 |
The main trade-off for timber sashes is maintenance frequency versus aesthetic and heritage value.
Timber sashes require repainting or re-oiling every 5–7 years, compared to uPVC (no painting for 20+ years) or aluminium (factory finish lasts 15–20 years). Untreated timber sashes can rot in 3–5 years if not painted (GGF 2026 maintenance guide).
For a conservation area or listed building, timber is often the only permitted material. uPVC is refused by the local planning authority in nearly all cases (Historic England, 2025).
Factory-finished engineered timber (for example, Accoya or modified pine) carries a 10-year manufacturer guarantee against rot and extends the repaint cycle to 10–12 years. However, it costs 20–30% more than standard timber (GGF, 2026).
You can verify a timber sash installer’s competence through MCS, TrustMark, and FENSA certification.
FENSA (Fenestration Self-Assessment Scheme) covers all replacement window installers in England and Wales. You can check a company’s FENSA registration online to confirm it can self-certify compliance with Building Regulations (FENSA, 2026).
MCS (Microgeneration Certification Scheme) is required only if the windows include integrated solar control or if you are claiming a grant such as the Great British Insulation Scheme. Most timber sash installers are not MCS-registered unless they also do energy-efficiency upgrades (MCS, 2026).
TrustMark is a government-endorsed quality scheme. An installer with TrustMark and FENSA has passed a vetting process for trading standards and customer complaints (TrustMark, 2026). Ask for a written guarantee of at least 5 years on the timber and 10 years on the glass (GGF 2026 code of practice). For listed buildings, the installer must have experience with conservation-area approvals. Check references or ask for previous listed-building installations.
Wooden sash windows are the most expensive sash option but the only one that can be repaired rather than replaced, which lowers lifetime cost.
A timber sash can be repaired — new cords, new glazing, re-routing of draught strips — for £200–£500 per window, compared to a full replacement at £1,200–£2,200 (Checkatrade 2026). uPVC sashes cannot be repaired in the same way. The whole frame must be replaced if the mechanism fails (GGF, 2026). Aluminium sashes are repairable, but the cost of replacement parts often approaches 70% of a new window (GGF, 2026).
The lifetime of a properly maintained timber sash is 60–80 years, compared to 20–30 years for uPVC and 40–50 years for aluminium (GGF 2026 durability guidance).
How to choose between uPVC and timber sash windows
Guide to secondary glazing for listed buildings
Frequently Asked Questions
A standard timber sash window (1.2m x 1.2m) costs £1,200 to £2,200 for supply and installation in 2026, according to Checkatrade cost tables. This is 40–60% more than uPVC sashes and 15–30% more than aluminium, as per GGF benchmarks.
Yes, if you commit to regular maintenance. Timber sashes offer better aesthetics and can last decades, but repainting every 5–7 years costs £150–£300 per window. For listed buildings, matching original profiles adds 25–50% to the cost (Historic England, 2025).
Yes, timber sashes with double glazing typically meet the 1.6 W/m²K whole-window U-value required by Building Regulations Approved Document L (2021 edition, updated for 2025). A well-sealed timber sash with 4-16-4 argon-filled double glazing achieves a centre-pane U-value of 1.2 W/m²K (Energy Saving Trust, 2026).
You need to repaint timber sash windows every 5–7 years, costing £150–£300 per window per repaint (Checkatrade 2026). Factory-finished engineered timber sashes claim a 10-year paint cycle but cost 20–30% more upfront.
Yes, draught-proofing a single-glazed timber sash can reduce heat loss by up to 50% (Energy Saving Trust, 2026). However, the window itself still falls short of the 1.6 W/m²K Building Regulations limit unless you also upgrade the glazing.
