uPVC vs Aluminium vs Timber Windows: Which Frame Material Is Best in 2026?

Quick answer: uPVC is the cheapest window frame material at roughly £400–£900 per fitted casement, aluminium typically costs 30–50% more, and timber costs the most upfront but lasts longest. All three can meet the 1.4 W/m²K U-value Building Regulations demand of replacement windows, so the real decision comes down to budget, looks and upkeep.

Frame material is the biggest decision you will make after the glazing itself. It sets the price of the job, how the house looks from the street, how much maintenance you sign up for, and how long it will be before you are paying for windows all over again. Here is how the three main options compare in July 2026.

uPVC vs aluminium vs timber at a glance

Sources: MyJobQuote window cost guide (updated 9 July 2026) · checked July 2026.

Cost: uPVC wins upfront, and it is not close

Fitted prices from MyJobQuote’s window cost guide (updated 9 July 2026) put a standard uPVC casement at £250–£400 for a small window, £400–£600 for a medium one and £600–£800 for a large one. Aluminium casements come in at around £550–£800 per window in the same guide, with larger sliding-sash aluminium styles reaching £800–£1,800. Timber starts at around £800 per window for softwood casements and can pass £2,500 for hardwood sash designs.

Across a whole house, our modelled estimate for a typical double glazing replacement is £5,530 at the national mid-point, with a typical range of £3,595–£8,572 (see how we calculate costs). Frame choice is one of the biggest levers inside that range: stepping up from uPVC to aluminium or hardwood timber across ten windows can add several thousand pounds. Our 2026 window replacement cost guide breaks the figures down per window and per UK region.

Energy efficiency: the glass matters more than the frame

Every replacement window in England must now achieve a U-value of 1.4 W/m²K or better — or a Window Energy Rating of band B or above — under Approved Document L. The transitional allowance that let timber windows meet a softer 1.6 W/m²K standard ended in June 2023, as the British Woodworking Federation notes, so all three materials are now held to the same bar.

In practice, all three clear it comfortably when paired with a decent sealed unit using low-E coated glass and argon fill. Bare aluminium conducts heat readily, so only consider frames with a polyamide thermal break — standard on reputable modern systems, and the reason the best systems can reach whole-window U-values close to 1.0 W/m²K. Beyond that, the bigger efficiency gains usually come from the glazing specification rather than the frame: our guide to double vs triple glazing runs those numbers, and BFRC window energy ratings explain the A++ to E labels you will see on quotes.

Lifespan and maintenance: timber outlives everything — if you look after it

uPVC is the low-effort option: an occasional wipe-down, plus new gaskets or friction hinges as they wear. Trade guides typically put its working life at 20–35 years, though south-facing white frames from older production runs can discolour sooner. Aluminium is similarly hands-off — its powder-coated finish is highly durable and lifespans of 40 years or more are commonly quoted.

Timber is the outlier. Left unmaintained it deteriorates fastest of the three; repainted or re-stained every five to eight years it will routinely last 50–60 years or more, and factory-finished modern timber stretches redecoration intervals further. On a whole-life view, a timber window costing half as much again as uPVC but lasting twice as long can work out cheaper per year of service — provided you actually do the maintenance.

Which frame material should you choose?

• Tight budget, standard home: uPVC. It meets Building Regulations, insulates well and costs least — and the money saved often does more good spent on a better glazing spec.
• Contemporary look or big glazed openings: aluminium. Its strength allows slimmer sightlines and larger panes than uPVC can safely carry.
• Period property or conservation area: timber. Some conservation areas and most listed-building consents effectively require it — check with your council before ordering, and see our FENSA and Building Regulations guide for the paperwork.
• Timber looks without the repainting: aluminium-clad timber hybrids exist at a premium. Composite constructions are more common in doors — our guide to composite doors covers those.

Whichever material you pick, settle the glazing spec first — that is where heat is won or lost. Our double glazing guide walks through the options, and our savings calculator estimates what new windows could take off your bills.

FAQs

Which window frame material is cheapest?

uPVC, by a clear margin — typically £400–£900 per fitted casement against £600–£1,600 for aluminium and £800–£2,800 for timber. It is also the cheapest to maintain across its lifetime.

Do all three frame materials meet UK Building Regulations?

Yes. Replacement windows must achieve 1.4 W/m²K or Window Energy Rating band B, and modern uPVC, thermally broken aluminium and properly specified timber windows all comply when fitted with a suitable double-glazed unit.

How long do timber windows last?

Well-maintained timber windows commonly last 50–60 years or more — longer than uPVC (20–35 years) or aluminium (40+ years) — but they need repainting or re-staining roughly every five to eight years to get there.