In short: uPVC windows cost less upfront (£550–£800 per frame supplied and fitted) and need less maintenance, but timber windows last two to three times longer, suit period London properties far better, and can add 5–10% to property value in conservation areas. Over a 25-year ownership period the total cost is broadly comparable — so the right choice depends more on your property type and priorities than on price alone.
Upfront Cost: uPVC Is Cheaper
There’s no getting around it: uPVC windows cost less to buy and install. In London in 2026, expect to pay £550–£800 per frame supplied and fitted for standard uPVC casement windows. Timber casement windows cost £900–£2,000 fully fitted — typically 60–110% more than uPVC – and bespoke timber sash windows built to heritage specification run to around £1,950 per window. For a whole-house project, that difference adds up quickly.
For a detailed breakdown by window type, see our guide to timber sash window costs in London.
Lifespan: Timber Wins by a Wide Margin
uPVC frames typically last 20–25 years before the seals fail and the frames need replacing. Timber, properly maintained, lasts 60 years or more — many original Victorian and Edwardian sash windows are still in service well over a century after installation. The trade-off is maintenance: timber needs repainting or re-staining roughly every 8–10 years, while uPVC needs only occasional cleaning.
Run the numbers over a full 25-year ownership period and the picture evens out considerably: uPVC typically costs £1,100–£1,600 all-in (purchase plus one likely full replacement), against £1,000–£1,650 for timber (purchase plus repainting cycles) — and at the end of 25 years the timber window is usually still good for decades more service, while the uPVC window is at or near the end of its life.
Appearance and Planning Restrictions
This is where the decision often gets made for you rather than by you. In conservation areas and on listed buildings, timber is frequently the only material planning officers will approve for front elevations — uPVC replacements of original timber sash windows are rarely given consent. If you’re not sure whether this applies to your property, see our guide on planning permission for sash windows in conservation areas before you commit to a material.
Outside conservation areas, on modern or non-period properties, uPVC is usually fine both aesthetically and in planning terms, and is the more practical choice for many homeowners.
Thermal Performance
Both materials can now achieve strong thermal performance with the right glazing specification. Modern timber frames with double or triple glazing perform comparably to uPVC, and in some cases better, because timber is naturally a poorer conductor of heat than the metal reinforcement inside uPVC frames. Our guide to double vs triple glazing in London covers the glazing side of the decision in more detail, regardless of which frame material you choose.
Property Value
In period properties, particularly in conservation areas, timber sash windows in good condition are widely recognised by estate agents and buyers as adding to a property’s value and kerb appeal — typically in the region of 5–10% according to industry commentary from bodies such as the Federation of Master Builders. Original or authentically restored windows are increasingly a selling point in period property listings, where uPVC replacements can be seen as a mark against a property’s character.
So Which Should You Choose?
- Choose timber if: you have a period property, live in a conservation area or listed building, want the longest possible lifespan, or want to protect or enhance property value.
- Choose uPVC if: you have a modern property with no planning restrictions, want the lowest upfront cost, and prefer minimal maintenance over a shorter working life.
Many of the London homeowners we work with start out assuming uPVC is the default and end up choosing timber once they see the full cost comparison and understand the planning position for their property. Our timber sash windows and uPVC sash windows pages set out the specification options for each.
Get a Like-for-Like Quote on Both Materials
If you’re weighing up timber against uPVC, we’re happy to quote both so you can compare real numbers for your property rather than general estimates. Get in touch for a free, no-obligation site visit.