The question we hear most on site visits. Short answer: it depends. The longer answer, what exactly it depends on, is below.
No material is better at everything. There's a material that's better for your building, your budget and your openings. Here's how we think it through when a client asks.
Price
PVC is noticeably cheaper. For a flat or house with standard windows, the difference can be enough to cover roller shutters and mosquito nets as well.
Insulation
A good multi-chamber PVC profile insulates excellently, no doubt there. Thermally broken aluminium is very close these days and, with good glazing, on a par. We don't recommend aluminium without a thermal break for living spaces.
Large openings
This is where aluminium wins. It's stiff, so it carries large, heavy glass without bending, and the frames stay slim. For a glass wall onto a terrace, that means more view and less frame.
Salt, sun and wind
Both materials cope well with coastal conditions. Aluminium doesn't corrode and powder coating is UV-resistant. Good PVC is UV-stabilised and steel-reinforced, so it doesn't yellow or warp.
One thing is often overlooked: dark colours in strong sun. Anthracite PVC on a south-facing wall heats up far more than white and expands more, which is why manufacturers limit the size of dark PVC sashes. If you want large dark windows on the sunny side, aluminium is the safer choice.
Looks
PVC comes in white, grey, anthracite and wood effects. Aluminium can be powder-coated in almost any RAL colour. For modern villas and shops aluminium is usually the architect's first choice; for flats and traditional houses PVC looks perfectly neat.
What we recommend in practice
- Flats and houses with standard windows: PVC.
- Villas, large glass walls, shopfronts and dark colours in full sun: thermally broken aluminium.
- Often best: a mix. PVC windows in the rooms and an aluminium sliding wall onto the terrace. You save money and get a big opening where it counts.
On the site visit we'll tell you what makes sense for each opening, and why.