uPVC vs uPVC/Aluminum vs Wood Aluminum Windows: Choosing a Frame for an Ontario Home
Internorm builds its tilt and turn windows three ways: all uPVC, uPVC with an aluminum weather shell, and real timber inside with aluminum outside. Their thermal values sit close together, so the choice comes down to looks, ageing and cost. Here they are side by side, with real model figures.
The short answer
Internorm's three frame types insulate almost equally, with best-case Uw values from 0.62 to 0.71 W/m²K, so choose on looks, upkeep and budget. uPVC is the most economical and white inside and out. uPVC/aluminum adds a powder-coated exterior in hundreds of colours. Wood/aluminum adds a real Spruce, Larch, Oak or Walnut interior. InterHaus in Oakville, Ontario, can mix the two clad types on one house.
What changes between the three frames, and what does not
All three Internorm families use triple glazing, triple gaskets, concealed tilt and turn hardware and glass bonded into the sash. That is why their best-case Uw values sit within 0.09 W/m²K of each other, from 0.62 on the KF 410 to 0.71 on the HF 520. What changes is the material you see and touch:
- uPVC (KF 310, KF 410, KF 510, KF 520): uPVC inside and out. See the uPVC range.
- uPVC/aluminum (the same four series): uPVC inside, aluminum outside; often called aluminum-clad or, in European spelling, aluminium-clad uPVC.
- Wood/aluminum (HF 410, HF 510, HF 520): timber inside, aluminum outside, bonded through a layer of thermal foam.
The three frame types side by side
Best-case figures from the Internorm 2026/27 catalogue and InterHaus product data. Ranges span the models in each family.
| uPVC | uPVC/Aluminum | Wood/Aluminum | |
|---|---|---|---|
| Interior face | White uPVC or I-tec Decor | White uPVC or I-tec Decor | Spruce, Larch, Oak or Walnut |
| Exterior face | White uPVC | Powder-coated aluminum | Powder-coated aluminum |
| Exterior colours | White | Hundreds, incl. RAL | Hundreds, incl. RAL |
| Core | Six-chamber uPVC | Six-chamber uPVC | I-tec Core LVL timber |
| Uw, best case (W/m²K) | 0.62–0.69 | 0.62–0.69 | 0.64–0.71 |
| Sound reduction, up to | 47 dB (KF 410) | 48 dB (KF 510) | 47 dB (HF 510, HF 520) |
| Security, up to | RC 3 (KF 510, KF 520) | RC 3 (KF 510, KF 520) | RC 2 |
| Construction depth | 71–90 mm | 74–93 mm | 85–90 mm |
| Passive House | KF 410 PHI certified | KF 410 PHI certified | Suited to PH and Net Zero |
| Lift and slide partner | KS 430 uPVC | KS 430 uPVC/aluminum | HS 330 |
| Relative cost | Lowest | Middle | Usually highest |
European whole-window Uw with optimum glazing; actual values depend on size and glass, and we confirm them on every quote. I-tec Decor is offered on the KF 310 and KF 410. Relative cost is our general guidance, not a price.
uPVC: the low-upkeep baseline
Internorm's uPVC is more rigid than standard vinyl and formulated to resist UV, so the white holds its colour and does not turn brittle. The 4 mm walls are non-porous, so they never soak up water or dirt. The windows are designed to last over 40 years, and the uPVC can be recycled up to seven times.
The trade-off is colour: the outside is white, and the KF 410 Studio and KF 310 Home Pure styles exist only with cladding. It suits brick homes where white frames work, rentals and cottages where upkeep matters most, and renovations with shallow walls, where the KF 310 is just 71 mm deep.
uPVC/aluminum: colour outside, the same warm core
A shell of powder-coated Grade A aluminum changes the face of the window without touching its insulation: the KF 410 reaches Uw 0.62 W/m²K either way, and the clad frame is only 3 mm deeper. The KF 510 even gains acoustically, reaching 48 dB clad against 46 dB in all-uPVC.
The shell takes the UV, sleet and wind-driven rain, and comes in hundreds of colours, from standard powder coats to metallic, stainless-steel-look and RAL finishes, with Internorm's warranty covering powder-coated surfaces against unnatural colour change and cracks. Choose it for dark or coloured frames and for houses that combine clad uPVC and timber rooms. See the uPVC/aluminum range.
Wood/aluminum: real timber where you live
Internorm's HF windows put factory-finished Spruce, Larch, Oak or Walnut on the room side and the same aluminum shell outside, so the timber never meets the weather. Green Building Canada's 2025 guide gives conventional wood windows 30 or more years with maintenance; the shell takes most of that maintenance away.
The I-tec Core is laminated veneer lumber, with a lower tendency than solid wood to twist, warp or split, which lets Internorm build large sashes on slim frames with 48 mm triple glazing and 73% light permeability. Choose it where timber should match floors or millwork, and for lakefront homes in damp, changeable conditions. The HF 410 comes in all four design styles.
How each frame handles an Ontario year
Deep cold
All three use Low Carbon iPlus glass as standard. The room-side pane stays around 21°C on a -10°C day with the room at 23°C.
Freeze and thaw
Non-porous uPVC holds no water to freeze and expand. In wood/aluminum, the timber stays indoors and the LVL core resists moisture.
Summer sun
Internorm uPVC is formulated to resist UV, and on clad windows the powder-coated shell takes the sun.
Humid rooms
Bathrooms and laundry rooms suit a wipe-clean uPVC interior; timber is happiest where the room is aired, which the tilt position makes easy.
Ground-floor security
Ontario’s Building Code requires windows within 2 m of the ground in a home to meet forced-entry requirements. The KF 510 and KF 520 reach up to RC 3; the HF series reaches RC 2.
Noise
Glass and gaskets do most of the work, so the three overlap: up to 47 dB on the KF 410 and 48 dB on the KF 510 uPVC/aluminum.
Relative cost, without guesswork
For comparable windows, all-uPVC is the most economical Internorm frame, uPVC/aluminum costs more for its shell, and wood/aluminum is usually the highest. RenoQuotes’ 2026 guide backs the first step, putting a vinyl-inside, aluminum-outside hybrid at $1,100–$1,400 against $800–$1,100 for vinyl; those are market estimates, not InterHaus prices. Our cost guide explains what drives a quote.
Comparing frame figures with Canadian ratings
Every Uw here is a European value. Canadian labels, ENERGY STAR and the Ontario Building Code use a U-factor rated under CSA A440.2 or NFRC at different test temperatures, and a 2014 RDH Building Science paper found the two can differ by up to 25% for the same frame and glass. The European figure applies directly to Passive House: the Passive House Institute’s cool-temperate criteria call for a component Uw of 0.80 W/m²K or less, and the KF 410 is certified in both uPVC and uPVC/aluminum.
Choosing your frame in five decisions
- 01
Exterior colour first
If white suits the facade, all-uPVC is open to you. A dark, metallic or RAL colour needs aluminum cladding.
- 02
Interior, room by room
Clad uPVC and timber-aluminum windows share the same shell, so timber in the living room and uPVC in the bathroom look identical from the street.
- 03
Performance needs
For a certified Passive House, start with the KF 410. Compare dB on a busy road, RC classes at ground level, and depth in a tight renovation wall.
- 04
Design style
Choose Studio, Home Pure, Home Soft or Ambiente, then check which family offers it. The KF 520 and HF 520 hide the sash from outside.
- 05
See the samples
Screens cannot show timber grain or a fine-structure coating. Compare them side by side at our Oakville showroom.
“This was a VIP experience from start to finish. Fast, friendly and effective service. It really helped that Vik is an architect, she was able to guide us through the entire process and coordinated directly with our designer. The windows are top-notch, but the service was better than the product.”
One team for all three frame types
As the official Internorm dealer in Canada, InterHaus supplies every frame on this page, plus all-aluminum Reynaers and Schüco systems, so our advice is not tied to one material. Our product specialists have an architectural background, architects and builders get technical support for their drawings, and orders run through local warehousing in Ontario, installed by our fitters or under our supervision. Projects range from the Etobicoke Passive House Residence to the Devil Lake Cabin and the Alcove PH Cottage in Québec.
Frame material questions
Neither has a meaningful thermal edge in the Internorm range: the KF 410 uPVC reaches Uw 0.62 W/m²K and the HF 410 wood/aluminum 0.64. Both are triple glazed with a warm inner pane, so the real differences are the interior surface and the price.
Both are rigid PVC; the difference is formulation and design. Internorm’s uPVC is more rigid and UV-resistant than standard vinyl, with 4 mm walls and six chambers, and is designed to last over 40 years without painting.
If you want an exterior colour other than white, yes: cladding is how you get it, and it unlocks clad-only design styles. If white suits the house, all-uPVC gives essentially the same insulation for less.
Not outside, which is powder-coated aluminum. The factory-finished timber inside is dusted and wiped gently, with indoor humidity kept in check by airing rooms. The care manual delivered with Internorm windows covers the details.
For timber inside, wood/aluminum is a strong choice: the LVL core is highly resistant to moisture and the shell takes wind-driven rain. For a cottage left empty all winter, uPVC or uPVC/aluminum asks even less of you.
Yes, if both are aluminum-clad. Internorm fits the same cladding to both and pairs the KF 510 with the HF 510 and the KF 520 with the HF 520, so the exterior stays uniform.
Explore each frame family
uPVC windows
KF 310 to KF 520 in six-chamber uPVC.
Explore
uPVC/Aluminum windows
The same four series with an aluminum weather shell.
Explore
Wood/Aluminum windows
HF 410, HF 510 and HF 520 with real-timber interiors.
Explore
Tilt and turn windows
The opening system all three share.
ExploreCompare the frames in person
Bring a floor plan or photos of the house to our Oakville showroom and handle uPVC, clad and timber samples side by side, or send drawings for a supply-and-install quote anywhere in Canada.
Sources
Product figures from the Internorm 2026/27 catalogue and InterHaus product data. External sources checked November 10, 2026:
- Energy Performance of Windows: Navigating North American and European Window Standards · RDH Building Science, 14th CCBST · 2014
- Ratings and certification · Natural Resources Canada
- ENERGY STAR Canada technical specification: windows, doors and skylights · Natural Resources Canada
- 2024 Building Code Compendium, Part 9 · Government of Ontario · Div. B 9.7.5.3
- Criteria for Certified Passive House Components: Transparent Building Components · Passive House Institute · v5.2, 2019
- Window Replacement Cost in Canada 2026 · RenoQuotes
- The Average Cost of Replacing Windows in Ontario · Green Building Canada