KF 520 uPVC/Aluminum Windows for Glass-Led Architecture
A powder-coated aluminum shell outside, a flush uPVC interior and a sash that disappears behind an 85 mm frame. The clad KF 520 gives a modern facade the look of fixed glazing, with operable windows wherever you need them.
What the aluminum-clad KF 520 brings to a project
Internorm describes the KF 520 as a combination of innovative design and technical know-how. Here is what that means on site.
Glass look, operable sash
From the street the sash is invisible and the window is indistinguishable from fixed glazing. Openers and fixed lights line up as one grid of glass and slim metal.
Aluminum weather shell
Grade A aluminum covers the exterior faces, finished in Internorm’s highly weather-resistant powder coating for colour stability.
Matches HF 520 timber/aluminum
The HF 520 shares the same exterior cladding, so you can put timber in the living spaces and uPVC elsewhere with no change to the facade.
I-tec Secure, standard
Integrated flaps lock the sash into the frame on all four sides, with no visible locking parts and security up to RC 3.
Exterior shading options
Venetian blinds and roller shutters can be positioned on the facade to shape its look and to control daylight and privacy.
33–46 dB with three gaskets
Three circumferential gaskets and triple glazing keep traffic and neighbourhood noise outside, a real advantage on an urban infill lot.
The KF 520, finished to suit the whole facade
The KF 520 is made for buildings where glass leads the design: long ribbon windows, stacked openings on a flat-roofed house, or a facade where every window should read as part of one rhythmic surface. The aluminum shell takes that idea further, because the slim 85 mm frame can then be finished to coordinate with metal fascia, railings or panels on the same elevation.
Internorm’s KF 520 brochure leans on greys for exactly this reason, noting that elegant shades of grey dominate modern architecture and highlighting EL02 stainless-steel look, HM735 and HM716 among its shells. Inside, the window is flush uPVC in white or dark grey.
Compared with the all-uPVC KF 520, performance is the same, Uw as low as 0.63 W/m²K and 33–46 dB, with a construction depth of 93 mm instead of 90 mm. The difference is how the facade looks and how freely you can choose its colour.
KF 520 uPVC/Aluminum technical data
| Construction | uPVC interior and core, aluminum exterior shell |
|---|---|
| Design style | studio (flush) |
| Thermal insulation, optimum | Uw as low as 0.63 W/m²K |
| Thermal insulation, standard coating | Uw 0.70 W/m²K |
| Sound reduction | 33–46 dB |
| Security | I-tec Secure standard; RC 1 N, RC 2 or RC 3 |
| Locking | Fully concealed, integrated in the sash |
| Construction depth | 93 mm |
| Sightline, frame | 85 mm, sash hidden from outside |
| Sightline, two sashes | 96 mm flying mullion · 148 mm mullion |
| Gaskets | 3 circumferential |
| Exterior colours | HM standard, HF/HFM hirest, HDS, EL01/EL02 stainless-steel look, RAL |
| Interior colours | White or Dark Grey uPVC |
| Expected service life | 40+ years |
Figures from InterHaus product data, the KF 520 brochure and Internorm’s 2026/27 technical overview.
Shape the look, outside and in
Every KF 520 starts with the same hidden sash. These choices decide how it reads on your house.
Grey aluminum shells
Internorm’s brochure highlights greys such as HM735 and HM716 for this window. They sit quietly against stucco, stone and fibre-cement cladding.
Stainless-steel look
EL02 gloss or EL01 matt for a metallic edge that frames the glass like a steel detail.
Fine-structure and metallic
Hirest HF and HFM finishes add subtle texture or metallic depth, in a special highly weather-resistant powder coating.
White interior
Bright and classic, with the flush frame and sash almost dissolving into a white wall.
Dark grey interior
A consistent dark frame that complements timber flooring and concrete and edges the view like a picture frame.
White inside, dark outside, one slim frame
The frame corner shows how the hybrid is built: the uPVC profile carries the insulation and the sash, and the aluminum shell covers the exterior face. The two finishes are chosen independently, so a black facade can sit over a white interior, or grey over grey for a monolithic look.
Smooth profile surfaces keep cleaning simple, and the glass is bonded to the sash all the way round. Because the sash hides behind the frame, an opener can sit in a row of true fixed lights and only the people inside will know which is which.
Where the frame is plastered in on three sides, the aluminum edge almost vanishes into the wall and the glass does the talking. Coordinate this with your builder early, because the reveal has to be detailed before installation.
Big glass, warm rooms, through a Canadian winter
A glass-led facade is only comfortable if the glass stays warm. With our standard iPlus Low Carbon double Low-E coating, a room at 23°C with −10°C outside keeps its inner pane around 21°C. That is the difference between a window wall you can sit beside in January and one that radiates cold and gathers condensation along its edges.
Internorm lists the clad KF 520 at Uw 0.70 W/m²K with the standard coating and as low as 0.63 W/m²K with the optimum glazing. On a glass-heavy elevation the narrow profile works in your favour: triple glazing outperforms the frame, so the more of each opening that is glass, the better the whole window performs.
Summer matters too. West and south glass can overheat a modern house, so we tune Ug and SHGC per elevation from more than 400 glass combinations and, where needed, plan exterior Venetian blinds or roller shutters. For certified builds, InterHaus can quote Passive House projects within 72 hours.
- Inner pane around 21°C at −10°C outside
- Uw as low as 0.63 W/m²K (0.70 standard coating)
- Adjustable Ug and SHGC per elevation
- Aluminum shell over a 360° insulated, reinforced uPVC frame
I-tec Secure, built into every clad KF 520
Large glass areas can make a house feel exposed. The KF 520 answers with Internorm’s I-tec Secure, standard on every unit. Flaps concealed in the sash open as the handle turns and press into the frame interior on all sides; Internorm calls it unrivalled in the industry, because levering the window out becomes virtually impossible.
Specify RC 1 N, RC 2 or RC 3 to suit each opening. Add laminated VSG glass, which holds together in the frame if broken, on ground-floor and street-facing windows, and handle-operated opening sensors that report by radio or cable whether each window is open, tilted or locked.
Because there are no visible locking parts, security never interrupts the clean lines inside or out, and the smooth rebate stays easy to wipe down.
Opening types for the clad KF 520
Lay out fixed lights and tilt & turn, turn-only or tilt-only sashes in one frame or across a whole elevation. On a stair, a double-height wall or a long kitchen run, put the opener where you can reach the handle; the view from outside will not change.
KF 520 uPVC/Aluminum vs. its siblings
The HF 520 is the timber/aluminum twin of the KF 520 and shares its exterior cladding. The KF 410 and KF 510 are the other aluminum-clad uPVC options.
| KF 410 | KF 510 | KF 520 | HF 520 | |
|---|---|---|---|---|
| Interior material | uPVC | uPVC | uPVC | Timber |
| Design style | studio, home pure, home soft, ambiente | home pure | studio | studio |
| Uw, optimum (W/m²K) | 0.62 | 0.64 | 0.63 | 0.71 |
| Sound reduction (dB) | 34–47 | 34–48 | 33–46 | 35–47 |
| Security, up to | RC 2 | RC 3 | RC 3 | RC 2 |
| Locking | Concealed | I-tec Secure | I-tec Secure | Concealed |
| Construction depth (mm) | 93 | 93 | 93 | 90 |
| Sightline, frame/sash (mm) | 113 | 95 | 85 | 101 |
uPVC/aluminum and timber/aluminum versions, from Internorm’s 2026/27 technical overview.
KF 520 uPVC/Aluminum: frequently asked questions
Both hide the sash and share the same exterior cladding, so they look alike from outside. The KF 520 reaches a lower Uw (0.63 against 0.71 W/m²K) and has I-tec Secure up to RC 3; the HF 520 brings a natural timber interior and up to 47 dB. You can also use both, timber in living spaces and uPVC in kitchens and bathrooms. Compare the HF 520.
Greys and stainless-steel looks keep attention on the glass, which is why Internorm’s KF 520 brochure features EL02, HM735 and HM716. For a precise match to other facade materials, the RAL programme is available in facade quality. Ask to see original samples before deciding.
Yes. Internorm offers Venetian blinds and roller shutters that can be positioned on the facade in different ways, to control daylight and privacy and to change the look of the elevation. Plan them with the window order so they are detailed into the wall. If you would rather keep shading inside the glass, see our integrated blinds.
The shell is Grade A aluminum in a highly weather-resistant powder coating, over a uPVC frame insulated and reinforced all the way round. The hybrid expands and contracts less than many other frame materials on the market, which helps it stay tight through freeze-thaw cycles.
No. Both reach Uw as low as 0.63 W/m²K and 33–46 dB. The clad version is 93 mm deep rather than 90 mm, so make sure the installation detail reflects the extra 3 mm.
Yes. Our product specialists have an architectural background and provide technical support to architects and builders, from elevations and glazing specifications to installation guidance and supervision on site.
Continue exploring
HF 520 timber/aluminum
The timber twin: the same flush exterior, natural wood inside.
Explore
KF 520 uPVC
The flush KF 520 with uPVC on both faces.
Explore
KF 510 uPVC/Aluminum
Square home pure profile with I-tec Secure and up to 48 dB.
Explore
KS 430 uPVC/Aluminum
Lift-slide doors with aluminum cladding for the terrace opening.
ExploreData sheets & brochures
Dimensions, profile sections, glazing build-ups and performance values — ready for your architect or builder.
Bring us your elevations
Whether it’s a new build or a deep retrofit, we’ll help you lay out fixed and operable KF 520 units, choose the shell colour and glazing, and quote supply and professional installation across Canada.