Timber Sash Windows: Softwood, Hardwood or Accoya?

New timber sash windows typically cost £1,200 to £2,500 per window in softwood and £1,800 to £3,500 in hardwood or Accoya, fitted. The timber you choose affects how long the windows last, how often they need painting and how smoothly they run. This guide compares the three main options, explains the glazing choices and tells you what to look for in a quote.

Softwood, hardwood or Accoya at a glance

	Engineered softwood	Hardwood	Accoya
Typical cost per window, fitted	£1,200 to £2,500	£1,800 to £3,500	Similar to hardwood
Typical lifespan	40 to 60 years	50 to 80 years or more	Guaranteed up to 50 years above ground
Repainting	Every 3 to 5 years	Every 5 to 8 years	Longer intervals, as the timber barely moves
Stability	Good if engineered	Good	Excellent
Best for	Good value, most homes	Durability, premium finish	Lowest maintenance, exposed walls

Softwood

Modern softwood sash windows are usually made from engineered (laminated) pine or redwood, which is much more stable than the cheap softwood used in the 1970s and 80s. With a good factory paint finish and regular maintenance, they are excellent value and suit most period homes.

Hardwood

Hardwoods such as oak, sapele and meranti are denser and naturally more durable. They hold paint well and suit high-end projects, oak frames and exposed sites. They are heavier, so the sashes need heavier weights or stronger balances.

Accoya

Accoya is a treated softwood that is exceptionally stable and rot resistant. It is light, holds paint for longer and comes with a long manufacturer guarantee. Read our full guide to Accoya sash windows.

Glazing options

• Single glazing: for listed buildings where original-style glass is required.
• Slim double glazing: thin units that allow slim glazing bars, the usual choice for period homes and conservation areas.
• Standard double glazing: the best insulation for the price, with slightly chunkier bars.
• Vacuum glazing: very thin and highly insulating; premium price.

For costs and options, see double glazed sash windows: costs and options.

Box sash with weights, or spiral balances?

Traditional box sash windows use cords, pulleys and weights hidden in the frame. Many new windows use spiral balances instead, which allow a slimmer frame. Weights are usually preferred on period and listed properties. Our guide to sash window weights vs spiral balances explains the difference.

Details that make windows look right

• Glazing pattern: match the house, such as six-over-six on Georgian homes or two-over-two on Victorian ones. See our Georgian and Victorian window guides.
• Horns: the small extensions on the upper sash; common on Victorian windows, not on Georgian ones.
• Glazing bars: real or bonded bars with spacer bars look better than stick-on bars.
• Mouldings: ovolo or lamb’s tongue profiles to match the originals.
• Paint colour: usually white or off-white for period terraces; check local conservation guidance.

What to ask for in a quote

• The timber species and whether it is engineered
• The glazing specification and U-value
• Weights and pulleys or spiral balances
• The paint system and number of factory coats
• Draught-proofing details
• Fitting, making good and disposal of old windows
• Guarantees on timber, paint, glass and workmanship
• Whether the installer can self-certify under building regulations (for example through FENSA or CERTASS)

Is replacement the right choice?

If your current windows are original and mostly sound, a restoration may cost far less. Read sash window repair or replacement before you commit, and check whether you need permission in a conservation area.

Get quotes for timber sash windows from installers near you.

Frequently asked questions

How much do timber sash windows cost?

Typically £1,200 to £2,500 per window in softwood and £1,800 to £3,500 in hardwood or Accoya, fitted, in 2026. London prices are usually higher.

How long do timber sash windows last?

Well-maintained softwood windows typically last 40 to 60 years, and hardwood 50 to 80 years or more. Many original Victorian sashes are well over 100 years old.

Is hardwood better than softwood for sash windows?

Hardwood is more durable and holds paint longer, but costs more. Modern engineered softwood is stable and good value. Accoya offers the best stability of all.

Are timber windows better than uPVC?

Timber looks more authentic, lasts longer and can be repaired, but costs more and needs painting. See our uPVC vs timber sash windows comparison.

Sources

Prices and lifespans from the Best Builders sash window cost guide, updated September 2026.