Sash windows · England
Triple glazed sash windows in Hertfordshire
We survey and fit triple glazed sash windows across Hertfordshire, from Watford and Hemel Hempstead to smaller towns such as Berkhamsted.

Honest advice on which sashes can take a full triple unit. A sash window has one or two sashes that slide up and down in a box frame.
Guide prices across Hertfordshire
Small window
about 600 x 1000 mm (bathroom, landing)
£1,295 – £1,595inc VAT · £1,080 – £1,330 ex VAT
- uPVC frame, triple glazed, warm-edge spacers
- Removal and disposal of the old window
- Fitted, sealed and made good inside and out
Medium window
about 1200 x 1200 mm (bedroom)
£1,695 – £2,095inc VAT · £1,410 – £1,745 ex VAT
- uPVC frame, triple glazed, warm-edge spacers
- Removal and disposal of the old window
- Fitted, sealed and made good inside and out
Large window
about 1800 x 1200 mm (lounge)
£2,595 – £3,195inc VAT · £2,160 – £2,660 ex VAT
- uPVC frame, triple glazed, warm-edge spacers
- Removal and disposal of the old window
- Fitted, sealed and made good inside and out
Guide prices, supply and fit. The written quote after your survey fixes the price for the specification shown; anything extra is agreed with you first.
Towns in Hertfordshire
- Watford
- Hemel Hempstead
- Stevenage
- St Albans
- Welwyn Garden City
- Cheshunt
- Hatfield
- Bishop's Stortford
- Borehamwood
- Hitchin
- Hoddesdon
- Letchworth Garden City
- Harpenden
- Bushey
- Hertford
- Rickmansworth
- Potters Bar
- Berkhamsted
Rules in England
The rules for replacement windows in England are set by Approved Document L (2021 edition, with 2023 amendments): 1.4 W/m²K, or a Window Energy Rating of band B or better. Replacement windows are a controlled fitting. A competent person scheme installer (such as FENSA or Certass) self-certifies the work and notifies the council within 30 days; otherwise a building control body approves it.
Planning: Replacing windows on a house is normally permitted development if the new ones look similar. New upper-floor windows in a side wall must be obscure glazed and fixed, or open only above 1.7 m. Flats and maisonettes have no householder permitted development rights, so a change that alters their appearance needs planning permission. An Article 4 direction in a conservation area may mean permission is needed, and listed buildings need listed building consent.
How it works
The surveyor measures every opening, checks ventilation, escape windows and safety-glass zones, and talks through styles. Your written quote lists each item with its glass build-up and U-value, and the price is fixed for that specification.
- Every opening measured, including escape and vent needs
- Frames rated for the weight of triple glass
- Old windows removed and taken away
- Each opening closed up the same day
Questions
Will triple glazing make my sashes heavy to lift?
The balances are sized for the sash weight, so they should slide smoothly. Heavier sashes use stronger balances or weights.
Are uPVC sashes allowed in conservation areas?
It depends on the council and any Article 4 direction. Timber is often expected on front elevations. Check before ordering.
How much do triple glazed sash windows cost?
Our guide starts at £1,295 for a small uPVC sash, fitted and inc VAT. Timber sashes cost more; UK quotes for timber triple sashes run past £3,000 each.
Do you cover all of Hertfordshire?
We arrange surveys and fitting across Hertfordshire.
Do I need permission for triple glazed sash windows in England?
In England, like-for-like replacements on a house are normally permitted development; flats need permission if the change alters their appearance, Article 4 areas may need permission, and listed buildings need listed building consent.
Sash windows in nearby areas of England
- Buckinghamshire
- Bedfordshire
- Greater London
- Surrey
- Essex
- Berkshire
- Oxfordshire
- Northamptonshire
- Cambridgeshire
- Kent
Other products in Hertfordshire
- uPVC windows
- Aluminium windows
- Timber windows
- Alu-clad timber windows
- Casement windows
- Flush casement windows
- Tilt and turn windows
- Bay and bow windows
- Fixed and picture windows
- Composite front doors
- French doors
- Sliding patio doors
- Bifold doors
- Glass-only replacement
- Acoustic triple glazing
- Security glazing
- Whole-house replacement
- New builds and self-builds
- Period homes and conservation areas
- Flats and apartments
- Passivhaus and EnerPHit
Sash windows across Hertfordshire
Written quote fixed for the specification, after a free survey. Building Regulations sign-off by a competent person scheme installer or building control, as the law requires in England.
