Glass-only replacement · Hertfordshire
Triple glazed sealed unit replacement in Potters Bar
Triple glazed replacement sealed units for homes in Potters Bar: measured on a free survey, made to order and fitted by installation teams working for us across Hertfordshire.

Straight advice on swapping glass only, and when it is worth it. Sealed unit replacement means changing only the glass in an existing frame.
Winter light and glass choice in Potters Bar
Winter days in Potters Bar are short: about 7 h 47 min of daylight on 21 December, with the sun peaking near 15°. That low angle reaches deep into south-facing rooms, so we match the glass to each elevation rather than using one spec for the whole house.
Guide prices in Potters Bar
| Guide | Supply and fit, inc VAT |
|---|---|
| Small unit up to about 0.6 m2, frame checked first | £145 – £195 |
| Medium unit about 0.6 to 1.2 m2 | £195 – £245 |
| Large unit about 1.2 to 2 m2 | £295 – £395 |
Guide prices. Your written quote after the free survey fixes the price for the specification shown.
Rules for glass-only replacement in England
England requires replacement windows to achieve 1.4 W/m²K, or a Window Energy Rating of band B or better, which good triple glazing passes comfortably. 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.
Before ordering: 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.
- Guide prices published, not hidden
- No pressure: the quote is yours to keep
- Frames, glass and fitting in one contract
- Advice on planning and consents before you order
Questions from Potters Bar
How much does a triple glazed sealed unit cost?
Where a frame can take one, our guide starts at £145 fitted for a small unit, inc VAT. Published UK figures of about £90 to £220 per unit are mostly for double units; triple units cost more.
Why are my windows misting between the panes?
The seal around the unit has failed and moist air has got in. Only replacing the unit fixes it.
Do I need permission for triple glazed replacement sealed units in Potters Bar?
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. Check whether your street is in a conservation area or covered by an Article 4 direction before changing the style.
Do you fit triple glazed replacement sealed units in Potters Bar?
Yes. We arrange surveys and fitting in Potters Bar and across Hertfordshire. Send your postcode and the windows or doors you want replaced, and we will book a free survey.
Nearby
We also cover nearby Hadley Wood (3 km), Barnet (5 km), Enfield (8 km) and Borehamwood (8 km).
Other products in Potters Bar
- uPVC windows
- Aluminium windows
- Timber windows
- Alu-clad timber windows
- Casement windows
- Flush casement windows
- Tilt and turn windows
- Sash windows
- Bay and bow windows
- Fixed and picture windows
- Composite front doors
- French doors
- Sliding patio doors
- Bifold doors
- Acoustic triple glazing
- Security glazing
- Whole-house replacement
- New builds and self-builds
- Period homes and conservation areas
- Flats and apartments
- Passivhaus and EnerPHit
Glass-only replacement in Potters Bar: book your free survey
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.
