Triple-Glazed uPVC Windows in Ontario, Engineered in Austria
Internorm's all-uPVC windows use the same six-chamber frame and triple glazing as our clad models, in a simpler white uPVC profile inside and out. Four series cover everything from slim renovation frames to sashless modern glass, with Uw values as low as 0.62 W/m²K. InterHaus supplies and installs them across Canada from our Oakville showroom.
The simplest Internorm window is not a compromise
An Internorm uPVC-all window is uPVC on both faces: the profile you see from the kitchen is the profile the weather sees. The missing aluminum shell is the only meaningful difference from our uPVC/aluminum windows. Chambers, gaskets, glass and hardware are the same, so the figures below are essentially those of the clad versions.
Leaving the cladding off works because Internorm extrudes its uPVC with 4 mm walls and a rigid, non-porous surface. It does not absorb dirt or moisture, so the white does not discolour over time, and it never needs paint.
For many Ontario projects that makes uPVC-all the sensible place to start: a brick home replacing tired double-hung units, a rental where upkeep matters more than colour, a cottage that sits empty all winter, or a new build where the budget is better spent on more glass. These windows are designed to last over 40 years with regular cleaning and a yearly drop of oil on the hinges.
Compare the four uPVC series
All four share six-chamber profiles, three gaskets and triple glazing; they differ in depth, sightline, design style and locking. The first Uw row is the best case with optimum glazing, the second the standard coating.
| KF 310 | KF 410 | KF 510 | KF 520 | |
|---|---|---|---|---|
| Uw, as low as (W/m²K) | 0.69 | 0.62 | 0.63 | 0.63 |
| Uw, standard coating (W/m²K) | 0.76 | 0.71 | 0.71 | 0.70 |
| Sound reduction (dB) | 33–45 | 34–47 | 34–46 | 33–46 |
| Security, up to | RC 2 | RC 2 | RC 3 | RC 3 |
| Locking | Concealed | Concealed | I-tec Secure, fully integrated | I-tec Secure, fully integrated |
| Construction depth | 71 mm | 90 mm | 90 mm | 90 mm |
| Sightline, frame + sash | 107 mm | 113 mm | 95 mm | 85 mm |
| Gaskets | 3 | 3 | 3 | 3 |
| I-tec Decor interior print | Available | Available | — | — |
| Design styles in all-uPVC | Home Soft, Ambiente | Home Pure, Home Soft, Ambiente | Home Pure | Studio |
Figures from InterHaus product data and the Internorm 2026/27 catalogue; final values depend on size, glazing and configuration, and we confirm them on every quote. KF 310 in Home Pure and KF 410 in Studio are built with exterior aluminum cladding only.
Why a European uPVC window is warmer than the vinyl you know
Six insulating chambers
Each profile is divided into six internal chambers that slow heat moving through the frame, so it stops being the weak spot around high-performance glass.
Three continuous gaskets
Triple-layer gasket seals run around the full perimeter as standard. They keep wind-driven rain out, make the window airtight and do much of the work behind sound reduction of up to 47 dB.
Triple glazing as the baseline
Triple-glazed units are what let uPVC reach Uw 0.62 W/m²K, performance up to twice as effective as the minimum Canadian ENERGY STAR requirement. Double-glazed uPVC rarely gets close.
Low Carbon iPlus coating
The standard double Low-E coating keeps the room-side glass at about 21°C when it is -10°C outside and 23°C inside, so a chair by the window stays comfortable in January. It still admits 74% of visible light.
I-tec Glazing bond
The glass is bonded to the sash all the way round. That stiffens the sash, improves insulation and sound values, and means the pane cannot simply be pushed out from outside.
I-tec Insulation fill
In the KF 410 and KF 510, insulating granules are pressed into the hollow frame chambers under pressure, filling them evenly and cutting heat loss further.
Why uPVC outlasts fiberglass and ordinary vinyl in Canada
Canadian windows get soaked, frozen, baked and frozen again, sometimes in the same week of March. Fiberglass can absorb moisture over time. Regular vinyl is softer and can turn brittle and fade under strong sun.
Internorm's uPVC is non-porous and completely water-resistant, so it will not warp, rot or swell in harsh weather. It is more rigid than standard vinyl and formulated to resist UV damage, so a south-facing elevation keeps both its colour and its stiffness. The surface also resists dust and dirt build-up.
- No repainting, sealing or refinishing
- Resists cracking, warping and fading through freeze-thaw cycles
- 4 mm thick extrusions for a rigid, durable exterior face
- Designed to last over 40 years
Opening types for every room
Every uPVC series is built around tilt & turn hardware, and each opening is specified on its own. Combine operable and fixed panes in one frame, use turn-only where a tilt is not wanted, or tilt-only for a high bathroom or basement window. Lockable doors and low-threshold doors use the same profiles.
Two ways to open, and why that beats a crank or a slider
Turn the handle up and the sash tilts inward at the top, a secure gap that lets air in and keeps rain out. Turn it sideways and the whole sash swings into the room like a door, so you can clean the outside pane from indoors and get full airflow on a hot July evening.
Compared with the window types most Ontario homes grew up with, that dual action solves real problems:
- Crank casements open one way only; a tilt ventilates without an open sash catching the wind.
- Double-hung windows never open more than half the frame; a turned sash clears the whole opening.
- Sliders open partially and collect grit in their tracks; tilt & turn sashes close onto three compression gaskets.
- Security: the sash opens inward and locks at multiple points, which makes it much harder to force from outside.
Four design styles, one performance standard
Internorm draws its windows in four profile shapes. In all-uPVC, the KF 410 covers three of them; the KF 510 and KF 520 own one each.
Studio
Flush and minimalist, with the glass as the design. In all-uPVC this is the KF 520, whose sash cannot be seen from outside.
Home Pure
Square edges and straight lines for contemporary houses. Available in the KF 410 and the slim KF 510.
Home Soft
Gently rounded edges that sit comfortably in almost any architecture, from a post-war bungalow to a new subdivision home. Available in the KF 310 and KF 410.
Ambiente
Contoured, profiled edges with classic detailing, the natural fit for heritage-style facades and traditional brick homes. Available in the KF 310 and KF 410.
Handles, glass and interior finishes
Every InterHaus window is built to the opening, not to a stock size. You choose from more than 20 handle options and over 400 glass combinations, sourced with trusted partners WinkHaus and AGC Glass. Glass can be tuned to a custom SHGC and Ug value: solar gain on a big south elevation, maximum insulation on a north wall.
Inside, the KF 310 and KF 410 can carry I-tec Decor, a digitally printed, UV-protected finish in thirteen designs, from Oak light and Walnut natural to Concrete grey, so frames can match floors or millwork. Depending on the series, decor colours such as Golden Oak or Dark Grey are also offered. If you want a coloured exterior too, that is the job of aluminum cladding.
Our product specialists have an architectural background and review every glass, hardware and opening choice with you or your designer before ordering.
All-uPVC or uPVC/aluminum?
Choose all-uPVC when white inside and out suits the house and you want Internorm performance at its most affordable. Choose uPVC/aluminum for a dark or custom exterior colour, the Studio look on a KF 410, or a facade that matches timber-aluminum windows. Thermal values are nearly identical, so the decision is about appearance and budget.
uPVC window questions we hear most
Yes, when frame and glass are built for it. Six-chamber profiles, three gaskets and triple glazing give Uw values from 0.62 to 0.69 W/m²K across the range, and a warm inner pane that minimizes cold drafts near the glass.
Yes. The KF 410 uPVC-all window is certified by the Passive House Institute, making it a strong choice for Passivhaus and EnerPHit projects. Send your drawings through our Passive House page and you will get a quote within 72 hours.
KF 310 is the slim one at 71 mm deep, good for renovations where wall depth is tight. KF 410 is the all-rounder, with the lowest Uw and three design styles. KF 510 adds slimmer sightlines and I-tec Secure locking up to RC 3. KF 520 is the minimalist choice: its sash is hidden from outside, so opening and fixed panes look identical.
Very little. Clean the frames when you clean the glass and oil the hinges about once a year; nothing else should be required. There is nothing to paint, seal or stain.
Internorm's uPVC windows can be recycled up to seven times, so material from today's frames can go into future windows. With a service life of more than 40 years, that is a strong environmental case.
Explore the uPVC range
KF 310 uPVC
Slim 71 mm frame with rounded or contoured edges, a proven choice for renovations.
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KF 410 uPVC
The most versatile series, Passive House certified, with I-tec Insulation in the frame.
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KF 510 uPVC
Slim square profile with fully integrated I-tec Secure locking.
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KF 520 uPVC
Flush design where opening sashes look like fixed glass from outside.
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uPVC/Aluminum windows
The same four series with a powder-coated aluminum weather shell in hundreds of colours.
ExplorePrice your uPVC windows
Send us drawings or window sizes and we'll recommend the series, glass and openings for each room, then quote supply and professional installation. Or see them first at our Oakville showroom, 217 Speers Rd. Unit 8.