Casement windows · Northern Ireland
Triple glazed casement windows in County Down
Triple glazed casement windows across County Down: free survey, written fixed quote, and fitting by installation teams working for us. Towns we cover include Bangor, Castlereagh and Downpatrick.

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.
Guide prices across County Down
Small window
about 600 x 1000 mm (bathroom, landing)
£695 – £845inc VAT · £580 – £705 ex VAT
- uPVC frame, triple glazed, warm-edge spacers
- Removal and disposal of the old window
- Fitted, sealed and made good inside and out
Medium window
about 1200 x 1200 mm (bedroom)
£895 – £1,095inc VAT · £745 – £910 ex VAT
- uPVC frame, triple glazed, warm-edge spacers
- Removal and disposal of the old window
- Fitted, sealed and made good inside and out
Large window
about 1800 x 1200 mm (lounge)
£1,395 – £1,695inc VAT · £1,160 – £1,410 ex VAT
- uPVC frame, triple glazed, warm-edge spacers
- Removal and disposal of the old window
- Fitted, sealed and made good inside and out
Guide prices, supply and fit. The written quote after your survey fixes the price for the specification shown; anything extra is agreed with you first.
Towns in County Down
Rules 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
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.
- 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
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.
What is an egress hinge?
A hinge that lets the sash open wide enough to climb out in a fire. It is used where a bedroom window is also the escape route.
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 you cover all of County Down?
We arrange surveys and fitting across County Down.
Do I need permission for triple glazed casement windows in Northern Ireland?
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.
Casement windows in nearby areas of Northern Ireland
Other products in County Down
- 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 across County Down
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.
