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Can I replace just one window pane?

Often you can, because a glazier can usually swap a single cracked or misted pane or sealed unit without replacing the whole frame. Whether that is sensible depends on the state of the frame, where the window is and whether the glass needs to be safety glass.

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By the QuoteZila editorial team. Editorial policy.

What counts as a window pane?

A window pane is one piece of glass held in a frame. Older single glazed sash and casement windows can have many small panes held in with putty or beads. Modern double glazed windows usually have one sealed unit per opening, made of two sheets of glass with a spacer and a gap between them.

That difference decides what replacement means. On an old timber window, a glazier may cut and fit a single pane of glass. On a double glazed window, they normally order a new sealed unit to the exact size and fit it into the existing frame.

QuoteZila is starting in Cheshire, with Crewe, Nantwich and Sandbach among the first towns, and anyone in the UK can post a job. This page covers the questions a glazier will ask, so your request is clear from the start.

Is the glass cracked, broken or misted?

Each fault points to a slightly different job:

  • Cracked but in place. Keep away from it, keep children and pets away, and do not press on it. Masking tape across a crack can stop pieces falling if it gets worse, but it is not a repair.
  • Broken with a hole. Board it or cover it from the inside if you can do so without handling loose glass. Some glaziers will board a broken window, so ask when you call.
  • Misted between the sheets. The seal on a double glazed unit has failed. It is not dangerous, but the window will insulate less well and the mist will not clean off.
  • Condensation on the room side. That is usually moisture in the room, not a faulty pane. Better ventilation helps more than new glass.

Never clear broken glass with bare hands. Gloves, a dustpan and thick card are safer, and a glazier can take broken glass away.

Is it just the pane, or the whole window?

Replacing one pane or sealed unit makes sense when the frame is sound, opens and shuts properly and has no rot or broken hinges. If the frame is rotten, warped or the locks and hinges are failing, a new pane will not fix that, and the glazier may suggest a new window instead.

The Planning Portal says building regulations have applied to all replacement glazing since 1 April 2002, covering things such as heat loss, safety and ventilation [S1]. FENSA, the scheme many window installers use to self-certify their work, says it covers replacement windows, doors, roof windows and roof lights, and does not cover repairs where the frame is not included [S2]. If you are only changing glass, ask the glazier what paperwork you will receive. If a whole window is being replaced, ask how they will certify it.

Where does a pane need safety glass?

Some glass has to break safely, which usually means toughened or laminated glass. The Planning Portal lists critical locations including glass within a glazed door up to 1500mm from floor level, and side panels to a door within 300mm of the door's edge, up to 1500mm from floor level [S1].

If the broken pane is low down, in a door or next to one, tell the glazier. They can check whether the replacement needs to be safety glass, which may change both the price and how long the glass takes to arrive.

Jobs you might post

These are examples, not taken from real job posts.

  • "One double glazed unit in the back bedroom has misted between the panes. The frame is fine."
  • "Cracked pane in an old timber sash window downstairs. Would like it replaced to match."
  • "Glass panel next to the front door has a crack across it. Not sure if it is safety glass."

Measure the glass if you can safely reach it, give the window style, and say whether it is the ground or first floor. Photos of the whole window and the fault help a glazier quote.

Questions about window panes

What is a window pane?

A pane is a single sheet of glass in a window. In a double glazed window, the two sheets are sealed together as one unit, and a glazier usually replaces that whole sealed unit rather than one sheet of glass on its own.

Why has my double glazed pane gone misty inside?

Mist or droplets between the two sheets of glass usually mean the seal around the unit has failed. Cleaning will not reach it. A glazier can usually replace the sealed unit and keep the frame, if the frame is still sound.

Does a new window pane need building regulations approval?

The Planning Portal says building regulations have applied to all replacement glazing since 1 April 2002, while FENSA says its scheme does not cover repairs where the frame is not included. Ask the glazier what paperwork they will provide, and ask building control if unsure.

Do I need safety glass in a window pane?

In some places, yes. The Planning Portal lists critical locations such as glazing in a door up to 1500mm from the floor, and side panels within 300mm of a door up to 1500mm from the floor. Low panes and panes near doors are the ones to ask about.

Does QuoteZila check the businesses?

No. We don't check insurance, qualifications or registrations, so please check these yourself before you hire. You can report a quote or a business from your job page.

Getting a glazier to quote

Citizens Advice suggests getting written quotes from at least three traders and asking for a fixed price rather than an estimate [S3]. For glass, ask each glazier whether the price covers measuring, making the unit, fitting, and taking away the old glass, and how long the new unit will take to arrive.

QuoteZila is free for customers and local businesses [QZ1]. Up to five matched local businesses can send you a quote [QZ2].

Honest status: QuoteZila is new. We're starting in Cheshire, beginning with Crewe, Nantwich and Sandbach, and growing area by area. Anyone in the UK can still post a job or register a business. How fast you get quotes depends on how many local businesses have joined near you. Businesses can register and receive jobs straight away. We don't check insurance, qualifications or registrations, so please check these yourself before you hire.

Posting a job is not open yet

See glaziers for glass and window work, or joiners if a timber frame needs repair before new glass goes in.

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Sources

  1. QZ1: QuoteZila product fact. QuoteZila home and jobs-for-tradesmen copy.
  2. QZ2: QuoteZila product fact. QuoteZila FAQ and app README.
  3. S1: Building regulations: doors and windows, Planning Portal. Accessed 2026-10-25. https://www.planningportal.co.uk/permission/common-projects/doors-and-windows/building-regulations/
  4. S2: Homeowners, FENSA. Accessed 2026-10-25. https://www.fensa.org.uk/homeowners
  5. S3: Before you get work done on your home, Citizens Advice. Accessed 2026-10-25. https://www.citizensadvice.org.uk/consumer/getting-home-improvements-done/before-you-get-building-work-done/