If you’re budgeting for new windows or doors in 2025, you’ve probably noticed prices can vary a lot. Material, sizes, glazing type and installation all play a role, and regional labour rates matter too. The good news: you can get a realistic estimate in minutes once you know what affects the final figure.
Below we explain the main price drivers, share example scenarios, and point you to a free tool that calculates a guide price based on your choices.
Get an instant estimate (free tool)
Rather than guessing, try a double glazing cost calculator that updates as you select window/door type, material, glazing and dimensions. Entering your postcode applies a small regional factor so you’ll see UK-appropriate guide prices including VAT and (optionally) installation.
What actually moves the price?
1) Material
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uPVC is usually the most budget-friendly for standard casements and many doors.
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Aluminium costs more but offers slim sightlines and strong, stable frames—popular for large spans (sliding or bi-fold doors).
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Timber is typically the premium option, valued for aesthetics and heritage properties, with more maintenance over time.
2) Size and configuration
Costs scale with width/height and with complexity. A wide window with multiple openers uses more hardware and fabrication time. Doors with extra panels or bespoke sizes add to the total.
3) Glazing type
Double glazing remains the UK default, while triple glazing adds weight, glass and spacer cost—expect a noticeable uplift. High-performance glass (solar control, laminated, acoustic) may add more.
4) Installation & access
Fitting, trims, disposal and making good can be 15–25%+ of a project depending on access, floor level and the number of units. Always compare like-for-like quotes that clearly separate supply and install.
5) Region
Labour and logistics differ between London/South East and other areas. Good calculators let you enter a postcode so you’re not using a one-size-fits-all national figure.
Example scenarios (illustrative)
These are not quotes, just examples of how variables affect price:
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Example A: 100×100 cm uPVC casement window (one opener), double glazed, supply & fit.
A simple, common size in a standard finish will sit toward the lower end of typical ranges. -
Example B: Aluminium 3-panel sliding door for a 3 m opening, supply & fit.
Larger moving glass with slim frames, more hardware and precise installation pushes costs higher than like-for-like uPVC.
Use the calculator linked above to plug in your sizes and preferred material for a more personalised guide.
How to avoid overpaying
Get comparable quotes. Ask for written, itemised quotes (frame spec, glass type, hardware, installation details, VAT). Side-by-side comparison is impossible without a like-for-like spec.
Check certifications. In England & Wales, replacement windows/doors must comply with Building Regulations. Use FENSA or Certass registered installers, and look for membership of trade bodies (e.g., GGF) for added consumer protection.
Clarify warranties. Confirm product and installation guarantees (what’s covered, who backs them, how long, and what the claims process is).
Look beyond headline discounts. A “50% off” sticker is meaningless without a baseline. Work from the spec and total price, not the percentage.
Mind access and extras. Upper floors, scaffolding, structural work, disposal and making good can change the final figure—ensure these are declared upfront.
Next steps
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Use the double glazing cost calculator to generate a guide price for your sizes and material.
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Shortlist a couple of local FENSA/Certass installers.
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Request like-for-like quotes and compare on specification, warranty and lead times—not just the headline number.
An informed brief + a quick calculator estimate will save you time and make your final quotes far easier to judge.