Window frame materials compared

uPVC, aluminium and timber each suit different homes, budgets and tastes. Here is how the three main window frame materials compare on the things that actually matter.

uPVC frames

uPVC is the most common choice in UK homes, and for good reason. It is the most affordable option, insulates well thanks to its multi-chambered profile, and needs almost no maintenance beyond an occasional wipe. Modern uPVC comes in a wide range of colours and woodgrain foils, so it no longer means only white. Its limitations are aesthetic and structural: profiles are chunkier than aluminium, and colour foils can fade over decades of sun. For most replacement projects on estates, semis and terraces, uPVC offers the best balance of price and performance.

Aluminium frames

Aluminium is prized for its strength, which allows slim sightlines and large panes of glass — ideal for contemporary extensions and big picture windows. It is durable, powder-coated in almost any colour, and resistant to warping. On its own aluminium conducts heat, so quality frames use a thermal break — an insulating barrier within the profile — to keep U-values low. Aluminium typically costs more than uPVC but less than premium timber, and it suits homeowners who want a crisp, modern look that lasts.

Timber frames

Timber offers a warmth and authenticity that synthetic frames struggle to match, which is why it is often specified in period properties, conservation areas and listed buildings. Well-made engineered timber is stable and can be repaired rather than replaced. The trade-off is upkeep: timber needs periodic repainting or re-staining to protect it from the British weather, and it usually carries the highest up-front price. For the right home, that investment buys character and, in sensitive locations, planning approval.

At a glance

Material	Relative cost	Maintenance	Best for
uPVC	Lowest	Very low	Value, everyday replacements
Aluminium	Mid to high	Low	Slim sightlines, modern homes
Timber	Highest	Periodic repaint	Period and conservation homes

Prices vary widely with size, style, glass specification and installer. The only reliable figure is a written quote after a home survey.

Matching material to glass and style

The frame is only one of the four decisions. Whichever material you pick, the glass inside it determines the thermal and acoustic performance — see our guide to double glazing glass types. The frame also has to suit the window shape, so it is worth reading our UK window styles guide alongside this page. For the full picture, return to the double glazing buyer's guide.