uPVC, aluminium or timber?
Different cost, different lifespan, different look. Describe the house and the AI tells you what suits style and budget.
Double glazing, sash repairs, skylights — A-rated frames, itemised quotes per window.
Read the brief on U-values, trickle vents and FENSA cert — then let Three local installers quote.
Different cost, different lifespan, different look. Describe the house and the AI tells you what suits style and budget.
U-values, BFRC ratings, Part L compliance, trickle vent rules, warm-edge spacers. Know what makes a window 'A-rated'.
Three local installers quote on the same spec — frame, glass, vent, install — so you can pick on quality.
Ready when you are
Enter your postcode and get free quotes from local pros.
Four moves that separate a smooth job from a nightmare.
Every new window must come with a FENSA or Certass building regs cert. Without it, your solicitor will refuse to exchange on the house sale.
Building Regs require U-value ≤ 1.4 W/m²K. Argon-filled, low-E coating, warm-edge spacers. Cheap quotes often skip these — and fail Building Control.
Since 2022, all replacement windows in habitable rooms need trickle vents. Quotes without trickle vents are pre-2022 — and not legal anymore.
uPVC frames settle, seals shrink, hinges drop. Hold 10% retention for six months and any post-install issues get fixed properly.
Indicative UK ranges and what affects price.
By job type
Quote spread is typically ± 18% — always get 3 quotes.
Visual breakdown of costs, timelines and the questions you should be asking.
Windows quick-view

Windows explained
Everything you need to know before hiring a windows.
Window installers and glazing specialists are essential for maintaining the comfort, security, and energy efficiency of your home. From replacing draughty single-pane units with modern double glazing to installing bespoke roof lanterns, these professionals handle everything related to the glass and frames in your property.
In the UK, window specialists work with a variety of materials including uPVC, aluminium, and traditional timber. Their expertise ensures that your home remains weather-tight while adhering to strict thermal performance standards required by current building regulations.
Whether you are looking to restore original Victorian sash windows or install high-performance triple glazing, hiring a qualified installer is the only way to guarantee a professional finish and a valid warranty for your investment.
A professional window installation or repair project typically follows a structured process to ensure accuracy and long-term durability. Here is what you can expect when you hire a specialist:
While DIY window fitting might seem like a way to save money, it is rarely advisable for several critical reasons. In England and Wales, replacement windows must comply with Building Regulations regarding thermal insulation, safety glazing, and ventilation (trickle vents).
Professional installers registered with schemes like FENSA or CERTASS can self-certify their work. This means they handle the legal paperwork for you, providing a certificate that is essential when you eventually come to sell your home. Without this, you may need to pay for a retrospective building control inspection.
Furthermore, a professional ensures the structural integrity of your home is maintained. They can identify if a specialist lintel is required above a new opening and ensure the windows are perfectly plumb to prevent future sticking, leaks, or "misted" glass units caused by seal failure.
The cost of window installation varies significantly based on the frame material, the number of "openers," and the complexity of the installation. Below are realistic 2025/26 estimates for standard UK installations including VAT.
| Service | Low £ | High £ | Notes |
|---|---|---|---|
| Standard uPVC Casement | £500 | £950 | Per window, white finish. |
| Timber Sash Window | £1,400 | £2,800 | Bespoke hardwood or Accoya. |
| Aluminium Window | £850 | £1,500 | Slimline frames, various colours. |
| Velux / Roof Window | £700 | £1,600 | Includes flashing and basic fitting. |
| Misted Double Glazing Repair | £120 | £300 | Replacing the glass unit only. |
| Bay Window Replacement | £1,800 | £3,500 | uPVC, 3-section to 5-section. |
Costs are influenced by factors such as the use of scaffolding for higher floors, the choice of coloured or wood-grain foils on uPVC, and whether you opt for triple glazing, which typically adds 20-30% to the glass cost.
Choosing the right trade professional is vital to ensure your windows last for their intended 20-25 year lifespan. Avoid high-pressure sales tactics and "limited time" discounts that seem too good to be true.
Questions to ask before hiring:
If there is condensation between the panes, the hermetic seal has failed. You do not usually need a whole new window frame; a glazier can simply measure and replace the individual glass unit (IGU), which is much cheaper and faster.
In most cases, replacing windows falls under "Permitted Development." However, if you live in a Conservation Area, an Article 4 Direction area, or a Listed Building, you will likely need formal consent from your local council before making changes.
Double glazing uses two panes of glass with an argon-filled gap. Triple glazing adds a third pane, significantly improving heat retention and sound insulation. It is ideal for north-facing rooms or homes near busy roads, though it is heavier and more expensive.
For an average 3-bedroom semi-detached house with 8-10 windows, a professional team can usually complete the installation in 2 to 3 days. This includes removing the old units and finishing the internal and external seals.
Describe the job in plain English. The AI asks a few smart questions, then tells you whether a windows is the right call, what it should cost, and what to ask before they start.
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