Glass-only replacement · Northern Ireland
Triple glazed sealed unit replacement in County Londonderry
From Derry to Magherafelt, we arrange triple glazed replacement sealed units for homes across County Londonderry, with every quote fixed for the specification shown.
Failed and misted units replaced, with frames checked first. Sealed unit replacement means changing only the glass in an existing frame.
Guide prices across County Londonderry
Small unit
up to about 0.6 m2, frame checked first
£145 – £195inc VAT · £120 – £160 ex VAT
- Triple unit made to measure
- Old unit removed and recycled
- New beads and glazing packers where needed
Medium unit
about 0.6 to 1.2 m2
£195 – £245inc VAT · £160 – £205 ex VAT
- Triple unit made to measure
- Old unit removed and recycled
- New beads and glazing packers where needed
Large unit
about 1.2 to 2 m2
£295 – £395inc VAT · £245 – £330 ex VAT
- Triple unit made to measure
- Old unit removed and recycled
- New beads and glazing packers where needed
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 Londonderry
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.
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
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.
- Guide prices published, not hidden
- No pressure: the quote is yours to keep
- Frames, glass and fitting in one contract
- Advice on planning and consents before you order
Questions
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.
Will heavier glass damage my hinges?
It can. Triple units are about 50% heavier, so hinges and packers are checked and upgraded where needed.
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 cover all of County Londonderry?
We arrange surveys and fitting across County Londonderry.
Do I need permission for triple glazed replacement sealed units 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.
Glass-only replacement in nearby areas of Northern Ireland
Other products in County Londonderry
- 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 across County Londonderry
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.