Glass-only replacement · County Antrim
Triple glazed sealed unit replacement in Belfast
If you live in Belfast (BT1) and want triple glazed replacement sealed units, start with a free survey: every opening measured, then a written quote that fixes the price.

Triple units for frames that can take them; better double units when they cannot. Sealed unit replacement means changing only the glass in an existing frame.
Winter light and glass choice in Belfast
On the shortest day, Belfast gets about 7 h 15 min of daylight and the midday sun reaches only about 12° above the horizon. Low winter sun means north-facing rooms here gain little solar heat, which is where triple glazing’s lower heat loss helps most.
Guide prices in Belfast
| 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
The rules for replacement windows in Northern Ireland are set by Technical Booklet F1 (2022): 1.6 W/m²K, or a Window Energy Rating of band C or better. 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
After the free survey you get a written quote naming the frame system, the glass build-up and the whole-window U-value for every item. Windows are made to order, then fitted, sealed and made good, one opening at a time.
- 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 Belfast
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.
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.
Do you fit triple glazed replacement sealed units in Belfast?
Yes. We arrange surveys and fitting in Belfast and across County Antrim. Send your postcode and the windows or doors you want replaced, and we will book a free survey.
Do I need permission for triple glazed replacement sealed units in Belfast?
In Northern Ireland, check with your council planning office before changing the style, material or size of windows, and always for listed buildings and flats. Check whether your street is in a conservation area or covered by an Article 4 direction before changing the style.
Nearby
We also cover nearby Castlereagh (4 km), Newtownabbey (7 km), Holywood (8 km) and Lisburn (11 km).
Other products in Belfast
- 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 Belfast: 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.
