uPVC-Steel Tilt-and-Turn Windows in Seattle

Grey uPVC double window in a light brick wall with a dark stone sill, reflecting a garden — Inspiration: European project

uPVC-steel

Multi-chamber frames, steel inside, triple glass. Our best value for a whole-house replacement.

Get a free consultation· See the 3 systems

A European uPVC window and an American vinyl window are made from the same family of plastic, and that's where the likeness ends. Our uPVC frames have six internal chambers, a steel profile running through the frame and sash, and two or three rubber gaskets that compress when the handle turns down. The result is a stiff, quiet, well-sealed window that costs less than aluminum or wood and needs nothing more than a wipe and a yearly drop of oil on the hardware.

What does "uPVC-steel" actually mean?

uPVC stands for unplasticized polyvinyl chloride. It's rigid PVC, without the softeners used in flexible plastics. On its own it insulates well but flexes. So European profiles put a steel reinforcement inside the main chamber of the frame and sash. The steel carries the weight of heavy triple glass and keeps a tall sash square for decades. The plastic around it does the insulating.

The chambers matter too. Each one is a pocket of still air that slows heat moving through the frame. More chambers and a deeper frame generally mean a warmer frame surface in January.

Cutaway corner of a white uPVC window frame showing the inner chambers, steel reinforcement inserts and triple glazing — System cross-section

Is uPVC better than American vinyl?

That difference shows up where Seattle windows usually fail: drafts at the meeting rail of a slider, whistling in a south wind, water at the sill. A tilt-and-turn sash closes like a refrigerator door, pressing evenly on its seals all the way around. And because the hardware is adjustable, a uPVC window that drifts over the years can be brought back into line with an Allen key. See European vs. American windows.

Our goal is simple: European energy-efficient windows for Greater Seattle homes, at an affordable price.
Petr Shypila, owner

Colors and looks that suit Northwest houses

White isn't the only option. Profiles come in a wide range of solid colors and woodgrain foils, and some systems use a color layer fused into the surface during extrusion, which holds up well to UV. Dark exterior colors, a white interior, or a woodgrain on one side only are all common choices. For a Craftsman or a 1940s box, a painted-look color with slimmer sashes (P-500) often reads closer to the original than a chunky white frame.

Dark-colored uPVC window frame and sill detail — Product detail photo

Where uPVC-steel fits, and where it doesn't

uPVC-steel is the right call for most replacement projects, rentals, ADUs on a budget and new builds where windows are standard to large. It's less suited to very large single sashes, extra-slim frames or floor-to-ceiling glass walls. Those are aluminum jobs. If you love wood inside, look at our wood and wood-aluminum windows.

Three uPVC-steel systems

	P-300	P-500	P-700
In one line	Best value	Slim, modern lines	Central gasket, passive-house-suitable options
U-factor from	0.15	0.15	0.15
SHGC range	0.14–0.38	0.14–0.38	0.17–0.42
Frame depth	3-3/16″ (81 mm)	2.9″ (74 mm)	3-1/4″ (82.5 mm)
Chambers	6	6 frame / 5 sash	6
Gaskets	2	3, incl. central gasket	3, incl. central gasket
Max glass thickness	54.8 mm	48 mm (50 mm bonded)	56 mm
Sound (Rw, European)	—	up to 47 dB	up to 45 dB
Variants	—	Light (slimmer sash)	Light, aluminum-clad
NFRC certified	Yes	—*	Yes
Page	P-300	P-500	P-700

U-factor in Btu/h·ft²·°F, best value from product data. Sound figures are European Rw ratings with acoustic glass, not US STC. A plain dash means no published figure. *— NFRC rating: ask us for current status for your project.

uPVC window questions

Do uPVC windows turn yellow or get brittle?

Modern European uPVC is UV-stabilized, and colored surfaces are either foiled or fused color layers. Like any material, finish life depends on exposure. We'll show you the finish options and what the maker says about them at the consultation.

Can uPVC windows be painted later?

It isn't recommended. Order the color you want. Woodgrain and solid colors are available from the factory.

Are uPVC windows strong enough for big openings?

Up to a point. The steel reinforcement handles typical residential sizes and heavy triple glass. For very large single sashes, we'll recommend aluminum.

Are uPVC windows recyclable?

uPVC profiles can be reground and re-extruded, and European profile makers run take-back programs. Ask us how we handle your old frames.

How long do they last?

With adjustment and seal care, European uPVC windows routinely stay in service for decades. Hardware and gaskets are replaceable parts, so a worn part doesn't mean a new window. Our windows carry a 20-year limited manufacturer warranty and a 3-year installation warranty; see warranty terms for details.

Have uPVC tilt-and-turn windows that drag, leak air or won't lock? Most are adjustable. Tilt-and-turn window adjustment →

Talk through uPVC-steel at your house

We measure at the house and go through frames, hardware and glass with you. The consultation is free.

Get a free consultation· (425) 678-5158

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uPVC-steel windows

What does "uPVC-steel" actually mean?

Is uPVC better than American vinyl?

Colors and looks that suit Northwest houses

Where uPVC-steel fits, and where it doesn't

Three uPVC-steel systems

uPVC window questions

Talk through uPVC-steel at your house

P-300 uPVC-steel

P-500 slim uPVC

P-700 central-gasket uPVC

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