There is no perfect window material. Every project needs a different approach, and what works in a detached house near Katowice is not necessarily the best choice for a glass-fronted villa outside Berlin. Below are the differences that really matter — without the brochure slogans.
uPVC — the best price-to-performance ratio
uPVC offers the best ratio of price to thermal performance. It works in most family homes and needs no maintenance at all: nothing to paint, nothing to oil. Modern uPVC profiles from VEKA, Kömmerling, Salamander or Gealan bring the Uw of the whole window down to 0.72–0.80 W/m²K, comfortably below the 0.9 legal threshold.
Aluminium — stiffness and large glazing
Aluminium is stiffer and makes bold, large glazing possible — the kind modern architecture loves: corner windows, floor-to-ceiling portals, heavy sliding doors. Because the metal itself conducts heat better than uPVC, a good aluminium profile must have a thermal break. In the Aluprof systems we sell it is standard; without it an aluminium window would not meet today's requirements.
Timber — natural insulation, with obligations
Timber is the best natural insulator and gives an interior a character no foil can imitate. It does, however, need regular maintenance: the coating has to be renewed every few years, especially on south- and west-facing sides. Timber-aluminium windows are the compromise: wood inside, a durable aluminium cladding outside.
None of these materials is universally best — each answers different needs. That is why our range includes all three, plus hybrid solutions.
How many chambers does a good uPVC profile have, and does it matter?
The number of chambers in a uPVC profile affects insulation, but it is not the only factor that counts — and more does not always mean proportionally better. Five-chamber profiles are today's market standard and work well in most homes. Six- and seven-chamber profiles add insulation that is noticeable mainly in very low temperatures or in passive houses, where every detail counts.
The final Uw is decided by the whole construction: chambers, profile depth and glazing quality together, not the chamber count taken out of context. A seller who advertises only the number of chambers without the Uw of the whole window is showing you half the information.
VEKA, Kömmerling, Gealan and Salamander in numbers
uPVC profile depths have been growing for years. Basic three-chamber profiles are about 60 mm; the top-of-the-range Kömmerling 88 MD is almost one and a half times that: 88 mm and 7 chambers. That brings the whole-window Uw down to 0.72 W/m²K — the lowest in this comparison.
- Gealan S 9000 — 82.5 mm, 6 chambers, Uw 0.75–0.80 W/m²K. Technical curiosity: the system uses STV technology, meaning the glass is literally bonded to the sash with double-sided tape instead of conventional glazing on plastic packers.
- Salamander bluEvolution 82 — 82 mm, 6 chambers, Uw 0.73–0.77 W/m²K. On the market since 2013 and still among the leaders, which in an industry where technology changes fast is a decent result.
- VEKA 82 MD — a class A profile: outer walls a few tenths of a millimetre thicker than class B. Nothing to the eye, but in a hailstorm or a break-in attempt those tenths decide whether the frame gives.
- Kömmerling 88 MD — 88 mm, 7 chambers, Uw from 0.72 W/m²K.
All four sit in a narrow Uw band of 0.72–0.80 W/m²K, each well clear of the 0.9 threshold. The difference is not that one is worse, but in small design details that may — or may not — matter to you.
How to choose in practice
Instead of asking "which material is best", ask: how large is the glazing, is the building new or are you replacing windows, how much maintenance are you prepared to do, and what is the budget. In the configurator you can build the same window in uPVC, aluminium and timber, compare Uw and request a quote in several systems at once — we reply within 48 hours.