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

Failed and misted units replaced, with frames checked first. Sealed unit replacement means changing only the glass in an existing frame.
Winter light and glass choice in Mitcham
Winter days in Mitcham are short: about 7 h 50 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 Mitcham
| 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
You will know exactly what you are buying: the quote states the unit build-up, frame, finish, fitting work and how Building Regulations compliance is handled. On fitting day each opening is replaced and closed up before the team moves on.
- Free survey and a written quote fixed for the specification
- Glass build-up and whole-window U-value on every quote
- Written handover pack at the end of the job
- Guarantees on frames, units and fitting in writing
Questions from Mitcham
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.
Can I put triple glazing in my existing windows?
Usually not in a way that helps. Most frames take up to about 28 mm units; a triple unit that thin performs about the same as, or worse than, good double glazing. We check your frames before recommending anything.
How long does it take to get triple glazed replacement sealed units fitted in Mitcham?
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 Mitcham?
Yes. We arrange surveys and fitting in Mitcham and across Greater London. Send your postcode and the windows or doors you want replaced, and we will book a free survey.
Nearby
Also near Mitcham: Morden (2 km), Wimbledon (4 km), Streatham (4 km) and Carshalton (4 km).
Other products in Mitcham
- 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 Mitcham: 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.
