Material that ages well.
Material choice largely defines window lifetime. Here's what we use, why, what spec we hold to — and who we buy from.
Aluminium
Alumil S-77 and S-91 series, Greek-made. 24–34 mm polyamide thermal break that interrupts heat transfer from aluminium to aluminium.
- Thermal break
- 24–34 mm
- U-value (profile)
- 1.2 W/m²K
- Min wall thickness
- 1.6 mm
- Warranty
- 10 years
Why aluminium? Permanent colour (anodised + powder coat), 50+ year lifespan, and for panoramic glass there's no real alternative.
PVC
Rehau Synego 70 mm profile, German-made. Five chambers, central steel reinforcement, rubber gasket for sealing.
- Chambers
- 5
- U-value (profile)
- 1.0 W/m²K
- Steel reinforcement
- 1.5 mm
- Warranty
- 5 years
Why PVC? Better profile-level thermal insulation, ~25% cheaper than aluminium, best for residential windows. Limitation: large sizes (3m+) push back to aluminium.
IGU (glass unit)
Triple-pane with Low-E coating and argon fill. 4-16-4-16-4 mm configuration, 44 mm total thickness.
- U-value (unit)
- 0.6 W/m²K
- Sound insulation
- 40 dB
- Light transmittance
- 74%
- Solar (g-value)
- 0.52
Low-E is an invisible metallic layer on the glass interior — it reflects summer solar heat outward and retains room heat inward in winter.
RAL colour
188 standard RAL colours, plus wood-effect foils (8 options) for PVC. Aluminium gets powder coat or anodising.
- RAL 9016Traffic white
- RAL 7016Anthracite grey
- RAL 8019Grey-brown
- RAL 9005Jet black
- RAL 7035Light grey
- RAL 9007Grey aluminium
Colour doesn't have to be the same inside and out — bi-colour windows are possible (PVC only).
A short glossary
Window terms you might want to recognise — short, no hand-waving.
- U-value
- Heat transfer coefficient. Lower is better insulation. A good window's total U-value lands around 1.0–1.4 W/m²K.
- Low-E coating
- An invisible metallic layer on the inner glass surface that reflects infrared radiation — retains room heat in winter.
- Argon fill
- Inert gas inside the IGU (instead of air) — better thermal insulation, doesn't degrade over time.
- Thermal break
- Polyamide insert between two aluminium layers that interrupts heat transfer. Critical for any aluminium window.
- Laminated (triplex)
- Two glass sheets bonded by a PVB layer — on impact it doesn't shatter, stays on the film. Used for safety.
- RAL standard
- European colour standard — 188 named/numbered colours. RAL 9016 is bright white, RAL 7016 anthracite grey.
- Tilt-and-turn
- Window opening mechanism — side-open + top-tilt from a single handle. The most common pattern in Europe.
- Sliding
- A horizontally sliding window sash. Common on balconies because it doesn't sweep into the room.
Ready to pick a material?
Step 2 of the configurator shows aluminium vs PVC with thermal coefficients and per-m² price.