Glass-only replacement · Dorset
Triple glazed sealed unit replacement in Dorchester
Looking at triple glazed replacement sealed units for a home in Dorchester? We survey, quote and fit across Dorset, and the DT1 postcode district is part of that.

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 Dorchester
By midsummer Dorchester has about 16 h 30 min of daylight, but in December only around 7 h 58 min, with the noon sun at about 16°. Triple glazing keeps more heat in during those long, dark months; big south and west windows may suit solar-control glass for summer.
Guide prices in Dorchester
| 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.
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
We start with a survey, not a sales pitch: measurements, the structure above any bays, trickle-vent needs and escape windows. The quote that follows fixes the price, and anything unexpected on the day is agreed with you first.
- 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 from Dorchester
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.
Will heavier glass damage my hinges?
It can. Triple units are about 50% heavier, so hinges and packers are checked and upgraded where needed.
How long does it take to get triple glazed replacement sealed units fitted in Dorchester?
After the survey, typical manufacture time is 1 to 2 weeks for units, and replacing the units usually takes a few hours to a day.
Do you fit triple glazed replacement sealed units in Dorchester?
Yes. We arrange surveys and fitting in Dorchester and across Dorset. Send your postcode and the windows or doors you want replaced, and we will book a free survey.
Nearby
Nearby towns on our list include Weymouth (12 km), Bridport (23 km), Yeovil (29 km) and Poole (32 km).
Other products in Dorchester
- 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 Dorchester: 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.
