How much do replacement windows cost in the UK?

Replacing windows is one of those jobs where the final bill depends on a surprising number of variables, so it's worth understanding the moving parts before you start collecting quotes. As a broad guide, uPVC windows typically cost somewhere in the region of £400-£1,200 per window fully fitted, with a whole-house job of eight to twelve windows commonly landing around £4,000-£14,000 depending on size, style and location. uPVC remains the most popular choice in the UK largely because it sits at the more affordable end of the market while still offering decent thermal performance and low maintenance.

Aluminium framed windows generally cost more than uPVC, roughly 25-40% more for an equivalent casement style, which in practice often works out around £550-£1,300 per window installed, or somewhere near £7,000-£13,000 for a full house. The premium reflects slimmer sightlines, a more contemporary look, and a frame material that tends to be very durable and low maintenance, though aluminium typically needs a thermal break built into the frame to perform well against heat loss, and this is worth asking installers about directly rather than assuming it's standard on every product.

Timber sits at the top of the price range and is usually the most expensive of the three. Basic timber casement designs commonly start from around £1,000 per window, while timber sash windows specifically often range from roughly £1,200-£2,500 in softwood, rising to somewhere around £1,800-£3,500 or more in hardwood. Hardwood in particular can add 50-100% on top of an equivalent uPVC price. Timber offers a traditional appearance that's often preferred, or sometimes required, on period properties and in conservation areas, but it generally needs more regular maintenance such as repainting or resealing to avoid rot, and its real-world lifespan depends heavily on how well it's looked after.

A number of factors push these figures up or down in practice. The number of windows being replaced matters, since whole-house jobs usually bring a better price per window than a single replacement, because fixed costs like scaffolding, skip hire and a fitter's day rate get spread more thinly. Glazing type is another factor: triple glazing commonly adds somewhere in the region of 20-40% on top of double glazing, and it's worth noting that some manufacturers don't offer triple glazing in certain styles, such as sash, because the extra weight makes the sash mechanism harder to operate safely. Opening style matters too, with standard casement windows generally the cheapest, tilt-and-turn typically adding around 25% over a standard casement, and sash or bay windows commonly costing 20-40% more, reflecting their added complexity. Finally, location plays a real role, with London and the South East typically commanding higher prices than the UK average, partly reflecting higher day rates for fitters in those regions.

When comparing quotes, it helps to know what should typically be included as standard: removal and disposal of the old windows, fitting of the new ones, making good the internal and external reveal (small areas of plastering or brickwork repair around the frame), and the mandatory FENSA or CERTASS certification confirming the work meets Building Regulations. A reputable installer will usually fold the certificate cost into the overall quote rather than charging separately, though a replacement certificate ordered independently later is a modest cost if you ever need one. VAT should also already be built into any quote you're given, so a "final" price that suddenly grows once VAT is added is worth querying. Extras that sometimes aren't included, and are worth clarifying upfront, include skip hire if not bundled in, decorating or plastering beyond a basic "making good," and any structural work needed if an opening is being altered rather than simply replaced like-for-like.

Weighing up durability, maintenance and lifespan across the three materials, uPVC generally offers the lowest maintenance and a reasonably long service life for the price, though its appearance is less traditional and it can look tired after many years of UV exposure. Aluminium tends to be very durable and slimline, ages well, and needs little upkeep beyond occasional cleaning, but the higher cost is worth weighing against those benefits. Timber offers the most traditional look and can last a very long time when well maintained, but it demands ongoing care, and neglect can shorten its lifespan considerably compared with the other two materials.

Ultimately, there's no single "right" answer between uPVC, aluminium and timber; the best choice depends on budget, property type, planning constraints (particularly in conservation areas or listed buildings, where timber may be required), and how much ongoing maintenance you're willing to take on. Because pricing varies so much by region, specification and installer, it's always worth getting several like-for-like quotes before committing, so you're comparing genuinely equivalent specifications rather than just a bottom-line figure.

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