Glass-only replacement · County Londonderry
Triple glazed sealed unit replacement in Derry
We arrange surveys and fitting of triple glazed replacement sealed units in Derry and the BT47 area, with a written, fixed quote after a free survey.

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 Derry
Winter days in Derry are short: about 7 h 10 min of daylight on 21 December, with the sun peaking near 12°. 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 Derry
| 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 Northern Ireland
Northern Ireland requires replacement windows to achieve 1.6 W/m²K, or a Window Energy Rating of band C or better, which good triple glazing passes comfortably. Replacing windows or external doors does not need full plans or a building notice, but the work must still comply; enlarging an opening or other structural change needs building control approval.
Planning: Check with your council planning office before changing the style, material or size of windows or doors, and always for listed buildings, conservation areas and flats.
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 Derry
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.
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.
How long does it take to get triple glazed replacement sealed units fitted in Derry?
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 Derry?
Yes. We arrange surveys and fitting in Derry and across County Londonderry. 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 Strabane (22 km), Limavady (24 km), Coleraine (44 km) and Omagh (44 km).
Other products in Derry
- 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 Derry: book your free survey
Written quote fixed for the specification, after a free survey. No building notice is needed for a straight replacement in Northern Ireland; we fit to the regulations and give you a written handover pack.
