Aluminium vs uPVC windows: for ordinary windows in a heated home, choose uPVC, because it costs less for similar insulation. Choose aluminium where uPVC falls short: large glazing, lift and slide doors, slim frames and colours from the full RAL range. If you want an aluminium look outside at a price closer to uPVC, there's a third option: a uPVC profile with aluminium cladding.
Aluminium vs uPVC windows: comparison table
| Criterion | uPVC | Aluminium (Aluprof) | |---|---|---| | Insulation | profiles 76–88 mm; Kömmerling 88 MD Uw from 0.73, Salamander bluEvolution 82 from 0.75 | MB-79N Uw from 0.95; MB-104 for passive buildings; MB-45 without thermal break, for unheated rooms only | | Price for the same size | lower | higher | | Large glazing and lift and slide doors | possible, but system limits come sooner | aluminium's strong point | | Frame width | wider | narrower, more glass in the same opening | | Colour | white in the base price; colour outside with white inside, or the same colour on both sides, from the profile brand's range | any RAL colour, always the same on both sides | | Care | profiles never need painting; seals and hardware need cleaning and lubricating now and then | powder coating; hardware and seals as with uPVC | | Typical use | windows in houses and flats, replacing old windows | patio glazing, corners, facades with lots of glass |
In both materials an opening sash must be at least 450 mm wide, and a door sash at most 2300 mm high (above that we add a fanlight). Detailed figures for the individual uPVC systems are in our article uPVC or aluminium: the differences in numbers.
When to choose uPVC
- You're replacing ordinary windows in a house or flat and watching the budget.
- You're building an energy-efficient house and want a low Uw without paying extra for the material. 82–88 mm systems with triple glazing give the most for their price here.
- White or a foil from the brand's range is enough for you: woodgrain, anthracite, grey, matt black.
When to choose aluminium
- You're planning floor-to-ceiling glazing, a corner without a post or wide lift and slide doors to the patio.
- The facade has a colour outside the uPVC ranges and you want it on both sides of the window.
- You want a slim frame and as much glass as possible.
- You're building a shopfront, an internal partition or an unheated conservatory: MB-45 without a thermal break is enough here.
More on large panes and sliding doors in our article on large glazing.
The third option: uPVC with aluminium cladding
Kömmerling 76 MD and 88 MD are available with aluminium cladding on the outside (AluClip). Inside you have a uPVC profile, on the facade side aluminium. It suits people who want an aluminium surface outside but prefer warmth and price closer to uPVC.
What to check in a quote, whatever the material
- The Uw of the whole window, not just the glass or the profile. You'll find it in the declaration of performance supplied with the delivery. How to compare quotes using it is explained in our article on the declaration of performance.
- Opening sides described as seen from inside. That's the most common correction we make to quotes, alongside the opening size given as the frame size.
- A top-mounted roller shutter from the start, because the box adds to the window's height.
- Unloading and fitting. Large panes, especially in aluminium, are heavy: unloading is up to you (forklift or 2–3 people) and your own team does the fitting. The 2-year GALI warranty doesn't cover damage from incorrect installation.
How to decide with your own project
We've worked with windows since 1997 and have exported them to the Netherlands, Germany and Switzerland since the late 1990s. That experience gave us one rule: we tell it straight, and if a cheaper system is enough, we'll say so in the quote.
The simplest way is to compare both materials with your own sizes. In the window configurator, build the same windows in uPVC first, then in aluminium: you see the price of each version straight away. The configurator also shows which systems offer a renovation frame and a Dutch-style frame (with or without a flange), since availability depends on the system. If you'd rather send a drawing or a list of sizes, use the contact form and tick up to 3 systems to compare. We'll prepare a quote with transport within 3 working days.
uPVC systems are described on the uPVC windows page and Aluprof systems on the aluminium windows page.