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. Every freeze / thaw cycle works old window seals loose and pushes single glazing further past its useful life, to the point where a replacement pays itself back in heating savings the first winter.

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Free 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

Weather: Open-Meteo historical archive, 2025 daily readings for Belfast.

Largest towns in Belfast

Newry81 companies Belfast66 companies Londonderry31 companies Omagh22 companies Craigavon20 companies Dungannon19 companies Armagh17 companies Ballymena17 companies Magherafelt15 companies Limavady14 companies Lisburn13 companies Banbridge11 companies

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All towns in Belfast

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)