Casement windows · County Antrim
Triple glazed casement windows in Belfast
Homes in Belfast can have triple glazed casement windows supplied and fitted, with surveys arranged across County Antrim including BT1.

Like-for-like replacement for most post-war homes. A casement window has sashes hinged at the side or top that open outwards, the most common window style in UK homes.
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 window about 600 x 1000 mm (bathroom, landing) | £695 – £845 |
| Medium window about 1200 x 1200 mm (bedroom) | £895 – £1,095 |
| Large window about 1800 x 1200 mm (lounge) | £1,395 – £1,695 |
Guide prices. Your written quote after the free survey fixes the price for the specification shown.
Rules for casement windows 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.
Before ordering: 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
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.
- 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
Can my existing casement layout stay the same?
Yes. We match the existing layout unless you ask for a change, which can matter for planning in conservation areas.
Do casement windows need trickle vents?
If the old windows had them, yes, and at least as large. If not, ventilation must be no worse than before. We size this on survey.
Do I need permission for triple glazed casement windows 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.
Do you fit triple glazed casement windows 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.
Nearby
Nearby towns on our list include 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
- 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
- Glass-only replacement
- Acoustic triple glazing
- Security glazing
- Whole-house replacement
- New builds and self-builds
- Period homes and conservation areas
- Flats and apartments
- Passivhaus and EnerPHit
Casement windows 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.
