Window & double glazing installers in Belfast
524 companies · 79 towns & cities
Belfast has 524 active window and glazing businesses on the Companies House register. Choose a town below to see the companies listed there, or request free quotes from FENSA or Certass registered installers covering your postcode.
Why Belfast homeowners are upgrading their windows
Belfast took 1,002mm of rain and 14 frost days in 2025. Those freeze / thaw cycles lift seals, warp frames and let moisture creep in behind older glazing.
Get 3 free quotesFree quotes below from FENSA / Certass installers active in Belfast. No obligation. Most respond within 48 hours.
Rainfall1,002mm
Frost days14
Peak gust136.1km/h
Temp range-3.7° to 28.1°C
Sources
Weather: Open-Meteo historical archive, 2025 daily readings for Belfast.
Largest towns in Belfast
Newry81 companiesBelfast66 companiesLondonderry31 companiesOmagh22 companiesCraigavon20 companiesDungannon19 companiesArmagh17 companiesBallymena17 companiesMagherafelt15 companiesLimavady14 companiesLisburn13 companiesBanbridge11 companies
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Newry (81)Belfast (66)Londonderry (31)Omagh (22)Craigavon (20)Dungannon (19)Armagh (17)Ballymena (17)Magherafelt (15)Limavady (14)Lisburn (13)Banbridge (11)Derry (11)Larne (11)Cookstown (10)Enniskillen (10)Antrim (9)Downpatrick (9)Bangor (8)Coleraine (8)Ballynahinch (7)Castlewellan (7)Co Down (6)Co Tyrone (5)Dungiven (5)Maghera (5)Newtownabbey (5)Ballyclare (4)Carrickfergus (4)Crumlin (4)Keady (4)Lurgan (4)Strabane (4)Castlederg (3)Newtownards (3)Ballymoney (2)Claudy (2)Co Antrim (2)Co Derry (2)Donaghadee (2)Feeny (2)Holywood (2)Kilkeel (2)Aghagallon (1)Annahilt (1)Annalong (1)Ardmore (1)Augher (1)Ballycastle (1)Ballygowan (1)Ballyhalbert (1)Ballymartin (1)Belcoo (1)Bellaghy (1)Bleary (1)Bushmills (1)Caledon (1)Carrickmore (1)Castledawson (1)Castlewaellan (1)Co Londonderry (1)Coalisland (1)Crossgar (1)Draperstown (1)Dromore (1)Drumquin (1)Eglinton (1)Gallbally (1)Garrison (1)Hamiltonsbawn (1)Letterbreen (1)Moneymore (1)Mowhan (1)Newcastle (1)Portadown (1)Portaferry (1)Rostrevor (1)Swatragh (1)Sydenham Business Park (1)