Aluminium Clad Wooden windows - Wood Inside, Maintenance-Free Outside

SOFT, Standard, Flush, THERMO, and THERMO PLUS - each with its own logic

Request a Free Quote Technical specifications

Uw up to 0.75 W/m²K

Thermal insulation

30-46 dB

Acoustic insulation

5 Years

Warranty

Uw from 0.77 W/m²K

What are Aluminium Clad Wooden windows?

All four variants follow the same principle: the laminated wood core provides thermal and acoustic insulation, while the aluminium profile on the exterior eliminates the need for repainting. They do not replace the wood—they cover it and protect it from UV rays, precipitation, and freeze-thaw cycles.

The difference between the variants lies in the aluminium profile: how well it integrates with the wood, the geometry of the joint between the sash and the frame, and how much it contributes to the frame’s thermal performance.

The Five Variants

Three series. Three levels of insulation. One uncompromising standard of execution for premium wood joinery.

Standard

Uses aluminium profiles from Gutmann or Uniform - a dedicated system that is more integrated than the direct cladding used in the SOFT variant. Features a classic joint geometry. Frame Uf 1.03 W/m²K.

THERMO

The THERMO aluminium profile features thermal insulation integrated into its structure. Frame Uf 0.82 W/m²K - compared to ~1.03 W/m²K for Standard and Flush variants. Uw at standard dimensions: 0.77 W/m²K.

SOFT

The basic variant: aluminium cladding applied directly to the wood profile. The wood retains its structural and thermal properties. The aluminium serves as protection, not as a separate system.

The wood profile can be IV68 (Uf ~1.36 W/m²K), IV78 (Uf ~1.03 W/m²K), or IV92 (Uf 0.91 W/m²K). Chosen when the exterior does not require periodic maintenance and there are no specific architectural requirements.

Flush (Coplanar)

Same base as Standard—Gutmann or Uniform profiles—but with different geometry. The sash is flush with the frame: viewed from the outside, there is no step. A continuous line across the entire window surface. Frame Uf ~1.03 W/m²K.

The difference from Standard is purely aesthetic. Thermal performance is identical. Flush (Coplanar) is used only when the architect has explicitly specified this coplanar variant.

THERMO PLUS

The variant optimized for maximum frame performance, with a lower Uf than THERMO: 0.77 W/m²K per frame compared to 0.82 W/m²K. Uw 0.75 W/m²K for the standard size with triple glazing Ug 0.6 W/m²K.

Can be configured with VIG glass (Ug 0.2 W/m²K) — in this combination, Uw drops below 0.5 W/m²K for standard-sized windows. The lowest thermal coefficient in the SM Wood wood-aluminium range.

Relevant for Passivhaus projects or any specification requiring a Uw value below 0.6 W/m²K for the window frame.

*Indicative pricing includes standard installation. Exact offer provided after a complimentary on-site measurement and technical assessment.

Uw wood-aluminium SOFT Standard THERMO variants

Technical specifications

Parameter	SOFT	Standard	Flush (Coplanar)	THERMO	THERMO PLUS
Base wooden profile	IV68 / IV78 / IV92	IV78 — 78 mm	IV78 — 78 mm	IV78 — 78 mm	IV78 — 78 mm
Exterior aluminium	Direct cladding	Gutmann / Uniform	Gutmann / Uniform	Gutmann / Uniform	Gutmann / Uniform
Frame Uf	Depends on base*	~1.03 W/m²K	~1.03 W/m²K	0.82 W/m²K	0.77 W/m²K
Standard Uw	~0.83 W/m²K	~0.83 W/m²K	~0.83 W/m²K	0.77 W/m²K	0.75 W/m²K
Uw with VIG (Ug 0.2 W/m²K)	—	—	—	Possibly < 0.55 W/m²K	below 0.5 W/m²K
Exterior geometry	Standard	Standard (stepped)	Flush / coplanar	Standard or coplanar	Standard or coplanar
Frame insulation	—	—	—	Available upon request	Available upon request
Glazing	40–44 mm glazing	40–44 mm glazing	40–44 mm glazing	40–44 mm glazing	40–44 mm glazing
Glazing U-value	0.6 W/m²K standard	0.6 W/m²K standard	0.6 W/m²K standard	0.6 W/m²K (0.2 W/m²K on request)	0.6 W/m²K standard / 0.2 W/m²K
Gaskets	3 x Schlegel Q-Lon	3 x Schlegel Q-Lon	3 x Schlegel Q-Lon	3 x Schlegel Q-Lon	3 x Schlegel Q-Lon
Standard hardware	Roto NX	Roto NX	Roto NX	Roto NX	Roto NX
Optional hardware	Roto NX Concealed, RC2, RC3	Roto NX Concealed, RC2, RC3	Roto NX Concealed, RC2, RC3	Roto NX Concealed, RC2, RC3	Roto NX Concealed, RC2, RC3
Exterior maintenance	Zero	Zero	Zero	Zero	Zero
Warranty	5 years	5 years	5 years	5 years	5 years
Lead time	8-12 Weeks	8-12 Weeks	8-12 Weeks	8-12 Weeks	8-12 Weeks

When it Makes Sense (and when it Doesn't)

The cost difference compared to a standard IV78 wooden window is justified by the elimination of periodic exterior maintenance. Without cladding, a wooden window requires repainting every 5-7 years. With aluminium cladding, no periodic exterior maintenance is needed.

The investment is worth it when

the glazed area is large and repainting cycles would involve significant labour costs.
the facade is directly exposed to precipitation or UV rays without eaves or other protection.
the project requires different interior/exterior colours - such as black or anthracite on the facade and a natural wood finish inside.
the architect has specified flush geometry or thermal performance exceeding Uw 0.81 W/m²K.

It may not be the best choice when

the budget is a primary constraint compared to simple IV78 - the cost difference is not always recovered.
Windows are protected by shutters, rollers, or other external protection - exposed wood on IV78 windows performs well with reduced exposure.
Wide eaves cover the windows - the lifespan of exterior wood increases substantially without direct exposure to rain and snow.

Available Wood species

The interior is wood - and it shows. Spruce is used for orders with opaque finishes. Oak is preferred when a transparent lacquer is chosen and the grain needs to remain visible. Meranti or Larch are species with natural moisture resistance - a significant advantage for standard IV78 windows. In aluminium-clad variants, the wood is protected by the aluminium, so the species has less impact on the facade's lifespan.

Spruce

Oak

Meranti

Larch

Pine

SM Wood Customer Experience

We trust the verdict of clients who sleep soundly through the deepest winter. That quiet confiden
ce is the testimonial that matters most to us.

Very good. Everything was according to the timelines and expectations!

Florin Lonca
Cluj-Napoca

Excellent! I am very satisfied with the collaboration in every respect: price, responsiveness, execution speed, and quality. I recommend them with confidence.

Marius Moldovan
Residential house project, Cluj

It was great working with smwoodprocom – the finished product was great, and what we expected. They are willing to go the extra mile to meet the client's needs and are flexible!

Jerome B.
Prébailly, France

Frequently Asked Questions

SOFT refers to the IV78 profile with aluminium cladding applied directly to the exterior. Gutmann and Uniform provide a more integrated industrial system with controlled geometry and the flush (coplanar) option. The frame Uf is identical for all three (~1.03 W/m²K). The difference lies in the finish, geometry, and the solidity of the profile, rather than insulation.

If the project requires a maintenance-free exterior and has strict energy efficiency specifications - yes. A Uw of 0.77 W/m²K compared to 0.81 W/m²K for the IV78 is a real difference in energy calculations, especially for large windows. If cost is the priority and nZEB is the requirement, a standard IV78 window covers it with a margin.

Yes. The aluminium exterior can be any RAL colour. The wood interior can be an opaque finish in a different RAL colour or a transparent lacquer on your chosen wood species. Independent colour combinations are one of the main reasons clients choose this variant over pure IV78 windows.

The frame U-value for all three is ~1.03 W/m²K. The final U-value depends on the window size and the selected glazing—approximately 0.80–0.85 W/m²K for a standard size with triple glazing (Ug 0.6 W/m²K), but the exact value is calculated based on your configuration. The table above marks these values with “~” for this very reason.

Yes. The THERMO version, with additional insulation in the frame, improves the thermal coefficient against the version without it. The exact values depend on the configuration; send us the dimensions and we will provide a calculation.

Yes, we manufacture and install throughout Romania.

Aluminium Clad Wooden Windows – Maintenance-Free Exterior