| How it opens | Casement on a crank, slider or hung sash; the screen sits outside or in the track | Tilt and turn on one handle: tilt at the head for ventilation, swing inward to clean; interior screens optional |
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| Frame | Hollow extrusions sized for the replacement opening and the hardware rather than the glass | Deep multi-chamber or thermally broken frames, 2 11/16 to 3 13/16 in (68-97 mm), with steel or polyamide cores |
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| Glass | Double glazing is the norm; triple is a premium add-on | Triple glazing to 2.83 in (72 mm) fits as standard; warm-edge spacers and argon by default on cold-climate schedules |
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| Sizes | Sash sizes limited by the hardware; big openings become mulled units | Single sashes to 9 ft 2 in (2.8 m) tall and lift and slide panels to 13 ft (4 m), confirmed per system |
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| Locking and seal | One or two cam locks, single or double weather strip | Multi-point locking around the full perimeter pulls the sash onto two or three continuous gaskets |
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| Performance paperwork | Domestic labels on the unit | European test data per system plus values in W/m2K and U-factor; code documentation confirmed per project with your building official |
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| Where it fits | Replacing like with like in an existing wall | New custom homes, deep renovations and additions where the openings are designed around the window |
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