Current UK pricing guides place standard double glazed sash windows at approximately £700–£1,500 per window. Timber sash replacement costs commonly range from £1,000 to £3,000, depending on the timber, window size and level of bespoke detailing.

​

These prices are intended for early budgeting. An accurate sash window replacement cost requires a survey of the existing openings and a written specification for each window.

​

​

What Affects Sash Window Costs?

​

Frame material

The choice between UPVC and timber has a significant effect on sash window prices.

​

UPVC is generally more economical and requires limited routine maintenance. Timber costs more initially but can provide a more authentic appearance and can usually be repaired and redecorated throughout its service life.

​

Hardwood and modified timber products will often cost more than standard engineered softwood.

​

Window size

Large sash windows require more frame material, heavier glass and stronger balancing mechanisms.

​

Tall Victorian or Georgian windows may also require additional installers to lift and position them safely.

​

Unusually shaped openings, curved heads and large bay windows will normally require bespoke manufacture and therefore cost more.

​

Double glazing

Double glazed sash windows contain sealed glass units rather than traditional single panes.

​

The glazing may include:

​

• Low-emissivity glass

• Argon-filled cavities

• Warm-edge spacer bars

• Toughened safety glass

• Laminated security glass

• Acoustic glazing

• Slim heritage units

• Obscure or decorative glass

​

Standard double glazing will usually cost less than slim-profile, acoustic or laminated glazing.

​

Opening mechanism

Traditional sash windows operate with cords, pulleys and concealed counterweights. Modern replacements may use either traditional weights or spring-balanced mechanisms.

​

Cords and weights can provide an authentic operating system but require space within the box frame. Spring balances may allow a slimmer construction and can be suitable where the original box is not being reproduced.

​

The chosen mechanism affects manufacturing complexity, installation and future maintenance costs.

​

​

Traditional detailing

Decorative and heritage features can increase the sash window cost.

​

These may include:

​

• Georgian glazing bars

• Decorative sash horns

• Deep bottom rails

• Traditional mouldings

• Lamb’s tongue profiles

• Period ironmongery

• Bespoke architraves

• Matching shutters and linings

​

A simple one-over-one sash will generally cost less than a multi-pane window containing narrow glazing bars.

​

Access

Ground-floor sash windows with straightforward access are usually less expensive to replace than upper-floor windows requiring scaffolding or specialist access equipment.

​

Costs may also rise where installers must work above:

​

• Conservatories

• Extensions

• Sloping roofs

• Pavements

• Public highways

• Restricted side passages

​

The quotation should confirm whether scaffolding, permits and access equipment are included.

​

​

UPVC Sash Window Costs

 

UPVC sash windows recreate the vertical sliding movement of traditional sash windows while providing modern double glazing, security and low-maintenance frames.

​

A typical UPVC sash window may cost approximately £700–£1,500 supplied and fitted, although smaller standard windows may fall below this range and large heritage-style units may exceed it.

​

UPVC sash window costs are influenced by:

​

• Window dimensions

• Number of opening sashes

• White or coloured frames

• Woodgrain finishes

• Georgian bars

• Decorative sash horns

• Deep bottom rails

• Tilt-in cleaning systems

• Glass specification

• Security hardware

​

White frames are normally the least expensive. Coloured and wood-effect finishes generally add to the price, particularly where different colours are required internally and externally.

​

UPVC sash windows can suit many traditional-style homes, but they may not be acceptable for listed buildings or sensitive conservation-area properties where timber is considered important to the character of the building.

​

​

Timber Sash Window Costs

 

Timber sash windows provide the most authentic option for Georgian, Victorian and Edwardian properties.

​

Current UK guides place timber sash window costs at approximately £1,000–£3,000 per window, with the price depending on whether the frame is manufactured from softwood, hardwood or a modified timber product.

​

Common timber options include:

​

• Engineered softwood

• Hardwood

• Oak

• Sapele

• Accoya

• Other modified timbers

​

A standard timber sash measuring around 600mm by 900mm has an indicative fitted cost of approximately £1,490, while larger bespoke hardwood or heritage windows can cost considerably more.

​

Timber frames require periodic maintenance, but properly constructed windows can be repaired, redecorated and upgraded rather than automatically replaced.

​

​

Double Glazed Sash Window Costs

 

Double glazed sash window costs depend on both the frame material and the type of sealed glass unit.

​

A standard UPVC double glazed sash will normally cost less than a bespoke timber version. Slim heritage double glazing, acoustic glass and laminated security glazing can all increase the price.

​

Double glazing costs may also rise where the frame needs to accommodate:

​

• Narrow traditional glazing bars

• Low-emissivity coatings

• Different glass thicknesses

• Toughened or laminated panes

• Specialist spacer bars

• Decorative glass

• Applied astragal bars

​

Current cost data places standard double glazed sash windows at roughly £700–£1,500 each, while timber replacements may extend to approximately £3,000 per window.

​

​

Double Glazed Wooden Sash Window Costs

 

Double glazed wooden sash windows combine traditional joinery with improved thermal performance.

​

They are commonly chosen for:

​

• Period houses

• Conservation areas

• Listed buildings

• Premium renovations

• Properties where original proportions must be reproduced

​

The cost will depend on the timber, glazing system, frame profiles and whether the windows are manufactured as standard products or made individually for the property.

​

A straightforward engineered timber sash may sit toward the lower end of the timber price range. Bespoke hardwood windows with slim double glazing, narrow glazing bars and traditional mouldings will normally sit toward the upper end.

​

For accurate comparison, each quotation should identify the timber species, glazing build-up, paint system and traditional details included.

​

​

Sash Window Replacement Costs

 

The complete sash window replacement cost may include considerably more than the manufactured frame.

​

A proper quotation should confirm whether it includes:

​

• Initial survey

• Manufacture of the window

• Removal of the existing frame

• Disposal and recycling

• Installation

• New cills

• Internal architraves

• External sealants

• Plaster repairs

• Redecoration

• Scaffolding

• Building Regulations certification

• VAT

​

Replacing the entire box frame will usually cost more than installing new sashes into an existing sound frame.

​

However, retaining a damaged or distorted box simply to reduce the price can result in draughts, poor operation and further repair costs.

​

​

Can Existing Sash Windows Be Repaired?

 

Original timber sash windows are often repairable, even where they appear badly worn.

​

Possible work includes:

​

• Replacing broken sash cords

• Renewing pulleys and weights

• Repairing decayed cills

• Splicing damaged timber

• Replacing individual sashes

• Renewing putty

• Installing draughtproofing

• Overhauling locks and catches

• Reglazing

• Repainting

​

Current UK cost guides place full sash-window restoration at approximately £620–£920 per window, although localised repairs can cost considerably less.

​

Repair may be particularly worthwhile where the existing windows contain good-quality timber, historic glass or fine traditional profiles that would be expensive to reproduce.

​

​

Repair, Upgrade or Replace?

 

Repair may be the better option where:

​

• The box frame remains structurally sound

• Timber decay is localised

• The window retains original detailing

• Cords, locks or seals are the main problem

• Planning policies favour retention

• The appearance of the existing window is important

​

Complete replacement may be more suitable where:

​

• Timber is extensively rotten

• The box frame is badly distorted

• Previous repairs have failed

• The window is insecure

• Replacement sashes cannot operate properly

• The existing design is unsuitable for the property

​

A specialist should inspect the windows and explain the cost of both approaches.

​

​

Sash Windows in Listed Buildings

 

Original sash windows can form an important part of a listed building’s historic character. Local authorities will often expect them to be retained and repaired unless they are genuinely beyond reasonable repair.

​

Where replacement is proposed, the new windows may need to match the originals in material, glazing pattern, opening style and moulding profiles. Detailed drawings may be needed to demonstrate the proposed construction.

​

Listed Building Consent may be required where the proposed work affects the architectural or historic character of the building.

Consent should be confirmed before windows are ordered or removed.

​

​

Sash Windows in Conservation Areas

 

Replacing sash windows in a conservation area does not always require planning permission, but restrictions may apply where an Article 4 Direction removes normal permitted development rights.

​

Flats and maisonettes also have different planning rights from single houses. Changing timber sash windows to UPVC may therefore require approval in some locations.

​

The safest approach is to check:

​

• Whether the property is listed

• Whether it lies in a conservation area

• Whether an Article 4 Direction applies

• Whether it is a house or flat

• Whether the material or appearance will change

• Whether original historic windows are being removed

​

Scaled elevations and detailed window drawings may be required as part of an application.

​

​

Building Regulations

 

Replacement windows are subject to Building Regulations requirements covering matters such as thermal performance, ventilation, safety glazing and means of escape.

​

An installer registered with an authorised competent-person scheme can normally self-certify qualifying replacement work and provide a compliance certificate. Otherwise, a Building Regulations application may be required.

​

The certificate should be retained because it may be required when the property is sold.

​

​

Comparing Sash Window Quotes

 

To compare sash window prices accurately, each installer should quote for the same specification.

​

Check that the quotation identifies:

​

• UPVC or timber construction

• Timber species where applicable

• Window dimensions

• Box sash or spring-balanced system

• Double glazing specification

• Glazing-bar arrangement

• Frame colour and finish

• Locks and security features

• Draughtproofing

• Removal of existing windows

• Making good

• Scaffolding

• Certification

• Product guarantee

• Workmanship guarantee

​

A quotation stating only “supply and fit sash windows” does not provide enough information for a fair comparison.

​

A lower price may exclude decoration, scaffolding, heritage details or complete removal of the existing box frames.

​

 

Find Trusted Sash Window Installers

 

Sash window costs should be considered alongside frame quality, architectural appearance, glazing performance and installation standards.

​

APN Double Glazing can connect homeowners with experienced local installers offering UPVC sash windows, timber replacements, double glazing, repairs and traditional window restoration.

​

Get in touch for expert advice and a free, no-obligation quote for your sash windows.