For tradespeople
For tradespeople

Double glazing companies in UK towns and cities

Choose a town for the firms that supply and fit replacement windows and doors in homes, in uPVC, aluminium or timber. Inside each town list, buttons keep only the companies that fit composite doors, bifold doors or sash windows. Each company page names the frames and doors it fits and where it works.

  • No company pays to get on a list
  • Pro and Top are marked every time
Builder in a hard hat measuring a new window frame in a red brick wall

Double glazing companies in towns and cities around the UK

Specialist work with its own lists

What homeowners ask before the work starts

Do replacement windows need a FENSA or Certass certificate?

In England and Wales, replacement windows and external doors must meet Building Regulations, for example on energy efficiency and means of escape. An installer registered with FENSA, Certass or another competent person scheme can certify the work and register it with the council, and you receive a certificate. Without one, the work needs Building Control approval. Keep the certificate, because a buyer’s solicitor will ask for it. Scotland and Northern Ireland have their own systems.

What should a double glazing quote include?

Every window and door with its size, frame material, colour, glass, energy rating, opening style and locks. It should also say whether taking out the old frames, disposal, trickle vents and making good inside and out are included, who will fit them, the lead time, the deposit and when the rest is due. Ask what the guarantee covers and whether the deposit and the guarantee are insurance-backed. Then compare quotes that describe the same products.

The salesperson offered a discount if I sign today. Should I?

There is no need to. A price that only lasts until the end of a home visit is a sales tactic, and the same company will usually still quote next week. Get at least one other written quote for the same windows before you decide. If you do sign at home, ask the company to set out in writing whether you can cancel and how long you have.

Can I replace sash windows in a listed building or a conservation area?

In a listed building, replacing or altering windows usually needs listed building consent from the council, and doing it without consent is a criminal offence. In a conservation area, some councils also control changes to windows at the front of houses. Speak to the council’s conservation officer first. Sash specialists can often repair and draught-proof old windows, make new timber sashes with slim double glazing or add secondary glazing, so ask which they suggest and why.

What should I ask about a composite or bifold door?

For a composite door, ask what the core and the outer skin are made of, which locks come with it and whether the doorset is tested to the PAS 24 security standard. For bifold doors, ask about the frame material, how many panels open and which way, the threshold and how it drains, and whether the opening has to be widened. A wider opening usually needs a new lintel or steel beam, which brings in Building Regulations.