Thermally broken profiles
Aluminium conducts heat well, so a modern aluminium window has a thermal break: a polyamide barrier that separates the inner and outer faces of the frame so heat is not carried straight out of the room. That construction is more involved than a single uPVC extrusion, and it is a large part of why aluminium costs more.
A good thermal break is not an optional extra. It is what stops cold frames and condensation on the inside, so it is worth checking on any aluminium quote.
Slim sightlines and larger panes
Aluminium is strong, so the frames can be much slimmer than uPVC for the same size of window, leaving more glass and a cleaner look. Slim sightlines are a main reason people choose aluminium. Larger panes of glass cost more to make and handle, so a window designed for maximum glass costs more than one divided into smaller sections.
Colour and dual colour
Aluminium frames are powder coated, which gives a hard, even finish in a wide range of colours. Greys and black are especially popular. Dual colour frames, with one colour outside and another inside, are a common choice and add to the cost compared with a single colour.
Glazing specification
The glass makes up most of the window, so it has a real effect on the price. Energy rating, coatings, acoustic glass for busy roads, laminated glass for security and obscure glass for bathrooms all change the cost. With aluminium's large panes, the glass spec matters even more than on a uPVC window.
- Double or triple glazing
- Energy rating and low-e coatings
- Acoustic or laminated glass
- Obscure glass for privacy
Size and opening type
Bigger windows cost more, and so do more opening sashes. A fixed pane is the simplest. Casements that open add hinges, handles and locking. Tilt and turn openers add more hardware again. Mixing fixed and opening panes in a sensible layout keeps cost down while still giving ventilation and an escape route where needed.
How aluminium compares with uPVC on cost
uPVC windows are the more affordable choice; ours start from £395 fitted. Aluminium costs more up front, but offers slimmer frames, a crisp powder coated finish and a very rigid frame. Both are low maintenance and both perform well thermally when specified properly.
Aluminium is often chosen for modern homes, extensions and large openings where slim frames make the most difference. uPVC is usually the better value for a whole-house replacement on a typical home. Our uPVC vs aluminium windows page compares them side by side.
Lifespan and value over time
Aluminium is a durable material that does not warp, and a powder coated finish wears well with occasional cleaning. That long life is part of the value. When comparing quotes, look past the headline figure to the profile, the thermal break, the glass and the hardware, and make sure fitting, removal and making good are all included.
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