KF 310 uPVC Windows: Slim, Proven Tilt & Turn in uPVC Inside and Out
The KF 310 is a compact Internorm tilt & turn window with a 71 mm frame, a six-chamber profile and three continuous gaskets. In the all-uPVC version both faces are uPVC, so there is no cladding to choose and almost nothing to maintain. It is the straightforward way to bring Austrian-built windows into a Canadian home.
Proven technology in a slim, low-upkeep frame
Internorm’s in-house product team built the KF 310 around technologies that have already earned their keep: a six-chamber frame profile, three continuous gaskets and I-tec Glazing, which bonds the glass to the sash all the way round. Nothing here is experimental, which is exactly why it suits a family home, a rental unit or a cottage that has to look after itself through a long winter.
At 71 mm, its construction depth is the shallowest of the four KF systems InterHaus carries, and the rounded edges of frame and sash give it the gentle profile of the home soft design style. In this version the window is uPVC inside and outside: no aluminum shell to specify, no exterior colour to coordinate and nothing outdoors that will ever need paint. More of the budget goes into glass, hardware and a careful installation.
Want a powder-coated colour outside? The same window is built as the KF 310 uPVC/Aluminum. Working toward certified Passive House performance? Step up to the KF 410 uPVC.
- Window replacements where a slim frame and generous glass area matter
- Bathrooms, laundry rooms and kitchens, where non-porous uPVC copes well with humidity
- Homeowners who want tilt & turn ventilation and triple gaskets on a sensible budget
KF 310 uPVC technical data
Best-case values for the all-uPVC KF 310, from the InterHaus data sheet and the Internorm 2026/27 catalogue.
| Frame material | uPVC inside and outside, six-chamber profile |
|---|---|
| Construction depth | 71 mm |
| Profile width | 70 mm frame + 36.5 mm sash |
| Sightline, frame and sash | 107 mm |
| Sightline, flying mullion (two sashes) | 119 mm |
| Sightline, mullion (two sashes) | 170 mm |
| Thermal insulation (Uw) | As low as 0.69 W/m²K; 0.76 W/m²K with the standard coating |
| Sound reduction | 33–45 dB |
| Security | Up to RC 2, fully concealed locking |
| Gaskets | Three continuous gaskets, light grey external gasket |
| Design styles in all-uPVC | home soft, ambiente |
| Interior finishes | White uPVC, decor colours or I-tec Decor digital print |
| Expected service life | 40+ years |
Actual values depend on window size, glass build-up and configuration; we confirm project figures with your quote.
What every KF 310 uPVC window includes
None of these are upgrades. They come with the window.
Six-chamber uPVC frame
Six internal chambers interrupt the path heat takes through the profile, and 4 mm outer walls give the extrusion its rigidity, keeping the frame’s inner face close to room temperature in deep cold.
Three continuous gaskets
Three circumferential seals keep wind-driven rain out and warm air in, and lift sound reduction to as much as 45 dB: enough to soften traffic, lawnmowers and a noisy backyard.
I-tec Glazing
The pane is bonded to the sash around its entire edge instead of simply sitting behind glazing beads. That bond stiffens the sash, helps it stay square through years of daily use and makes the glass very hard to push out.
Minimal upkeep
Clean the frames when you clean the glass and oil the hinges about once a year. uPVC is non-porous, so it will not rot, swell or ask for paint.
I-tec Decor interiors
If white feels too stark beside oak floors or walnut cabinetry, the inner uPVC face can be digitally printed in one of thirteen I-tec Decor designs, sealed with a top coat that resists UV and household cleaners.
KF 310 design styles in all-uPVC
Internorm builds the KF 310 in three design styles. Two are available with uPVC on both faces; the square-edged third is reserved for the aluminum-clad version.
home soft: rounded
Softly rounded edges on frame and sash give a calm, timeless look that sits naturally in almost any house, from a post-war bungalow to a new subdivision home.
ambiente: contoured
Profiled, contoured edges bring the classic detailing of a traditional window. Choose it for century homes, farmhouses and heritage streets where a flat modern frame would look out of place.
home pure: uPVC/aluminum only
The square-edged KF 310 is made only with the aluminum exterior shell. For straight contemporary lines, choose the KF 310 uPVC/Aluminum.
Warm glass through a Canadian winter
In its best configuration the KF 310 reaches a Uw as low as 0.69 W/m²K, and 0.76 W/m²K with the standard glass coating. Standard North American windows commonly fall between 1.2 and 2.0 W/m²K. A lower Uw means less heat leaves through every square metre of window.
Day to day, the figure that matters most is the temperature of the inner pane. With Internorm’s standard double Low-E coating using Low Carbon iplus technology, when it is −10°C outside and 23°C indoors, the room-side glass stays around 21°C. That is why you can sit beside a KF 310 in February without a cold draft falling off the glass, and why interior condensation becomes far less likely.
Old windows are often the weak point of a house: Internorm estimates that up to 30% of a home’s heat escapes through them. A tighter envelope also holds moisture in, so after showers or cooking, run the fan or tilt a window for a few minutes.
- Triple insulating glass with wafer-thin coatings and argon or krypton gas between the panes
- Glass that can be tuned to custom SHGC and Ug values for hot south- and west-facing rooms
RC 2 protection that stays out of sight
The KF 310 is rated up to resistance class RC 2. Every Internorm window ships with standard security hardware: solid, discreet locking elements with octagonal mushroom cams in the sash, plus concealed hinges that stop the sash being levered out. Tilt & turn windows also open inward, leaving no exterior crank or sash to attack.
I-tec Glazing adds another layer: with the pane bonded to the sash all round, the glass cannot simply be pushed out. A lockable handle keeps a window closed until you turn the key, and a turn lock allows tilt ventilation but not full opening, a sensible detail for children’s bedrooms upstairs. Laminated safety glass (VSG) holds a broken pane in place.
If your insurer, architect or own peace of mind calls for RC 3, look at the KF 510 or KF 520. Both carry Internorm’s I-tec Secure flap locking as standard, a system the KF 310 does not offer.
Opening types and combinations
Every KF 310 is made to measure, so the layout follows your room rather than a stock size: tilt & turn for bedrooms and living rooms, tilt-only for transoms and small bathroom windows, fixed lites for more view, or fixed and opening sashes combined in one frame. The same profile can be built as a balcony door or side door.
KF 310 against the rest of the all-uPVC range
The KF 310 has the shallowest frame in the line-up; the step-up models add frame insulation, slimmer sightlines or I-tec Secure.
| KF 310 | KF 410 | KF 510 | KF 520 | |
|---|---|---|---|---|
| Uw, best value (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 | I-tec Secure |
| Construction depth (mm) | 71 | 90 | 90 | 90 |
| Sightline, frame and sash (mm) | 107 | 113 | 95 | 85 |
| I-tec Insulation | — | Yes | Yes | — |
| Design styles in all-uPVC | home soft, ambiente | home pure, home soft, ambiente | home pure | studio |
Figures from the Internorm 2026/27 technical overview for uPVC windows and the InterHaus product pages.
“Excellent windows and doors for noise and heating and cooling. We had to install new windows in some rooms in our old house and the difference between these ones and our old ones was obvious right away, no condensation in the winter, much quieter in summer (we had very noisy neighbours), very little heat loss so the rooms were warmer in winter and cooler in summer. We were so impressed that we installed them throughout our new house. Viktoryiya was so easy to work with, and the installation was excellent and problem free!”
KF 310 uPVC: questions we hear
Internorm makes the square-edged home pure KF 310 only with the aluminum exterior shell. In all-uPVC you choose between rounded home soft and contoured ambiente. If straight lines matter more than a uPVC exterior, the KF 310 uPVC/Aluminum gives you home pure with a powder-coated outside face.
Internorm’s uPVC is rigid, non-porous and formulated to resist UV, so it does not absorb water, swell, rot or turn brittle the way basic vinyl can. Internorm’s warranty specifically covers white uPVC profile surfaces against unnatural colour change and cracking, mitre cracks excepted.
The KF 310 is a strong performer, with a Uw as low as 0.69 W/m²K, but for a certified Passive House or EnerPHit project InterHaus specifies the KF 410, which is certified by the Passive House Institute and reaches 0.62 W/m²K. For a high-performance renovation that is not chasing certification, the KF 310 is often all the window the house needs.
Yes. Beyond white, the inner uPVC face can carry I-tec Decor, Internorm’s digital-print finish in thirteen designs, including oak, walnut, spruce, beech and concrete-grey looks. The print is applied in several layers and sealed with a protective top coat.
Explore related windows
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KF 410 uPVC
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All uPVC windows
Compare the KF 310, KF 410, KF 510 and KF 520 with uPVC inside and out.
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KS 430 uPVC lift-slide door
Large sliding glass for the patio, in the same uPVC material.
ExploreData sheets & brochures
Dimensions, profile sections, glazing build-ups and performance values — ready for your architect or builder.
Plan your KF 310 uPVC windows
Send us drawings or a simple list of openings and we will prepare a KF 310 specification and quote. Prefer to see the hardware first? Visit our Oakville showroom at 217 Speers Rd. Unit 8 and open a tilt & turn window yourself.