F-Series · Fiberglass
GR70 Casement Window
A 70 mm outward-opening casement in pultruded fiberglass — the workhorse operable window for multifamily and modular elevations, and the frame shown across the eight factory finishes.
The casement swings outward on concealed hinges for a clean interior face and a full-perimeter seal that tightens under wind pressure. On a fiberglass frame it stays dimensionally stable through heat and cold, so the seal keeps its grip for decades.
Technical specifications
| Frame depth | 70 mm |
| Frame material | Pultruded fiberglass, powder-coated |
| Glazing pocket | Up to 40 mm |
| Opening | Casement, outward |
| Whole-window U-value, ZERO 04 | 0.143 Btu/h·ft²·°F (0.81 W/m²K), R-7.0, at NFRC size 600 × 1500 mm Calculated |
| Whole-window U-value, ZERO 05 | 0.147 Btu/h·ft²·°F (0.83 W/m²K), R-6.8 Calculated |
| Whole-window U-value, ZERO 24 double glazed | 0.249 Btu/h·ft²·°F (1.41 W/m²K), R-4.0, within the Massachusetts energy code Calculated |
| Center-of-glass U-value | ZERO 04: 0.044 to 0.047 Btu/h·ft²·°F (R-21 to R-23) · ZERO 05: 0.054 (R-18.5) Calculated |
| SHGC, center of glass | KØLD 0.49 / 0.35 · MILD 0.35 / 0.27 · HEIT 0.26 / 0.20 (ZERO 05 / ZERO 04) Calculated |
| Visible light, center of glass | KØLD 76% / 64% · MILD 67% / 53% · HEIT 61% / 45% (ZERO 05 / ZERO 04) Calculated |
| Finishes | 8 factory finishes |
Certified values are published as NFRC and CSA testing completes. Calculated values come from LBNL THERM and WINDOW models of the specific assembly. Project-specific values depend on size and glass package.
What is a casement window?
A casement window is hinged on one side and swings open like a door, usually outward. Because the entire sash opens, it ventilates fully and catches side breezes, and the harder the wind pushes on it, the tighter it seals against the frame. Casements give an uninterrupted view and a slim sightline.
Thermal section (THERM heat map)
GR70 Casement Window · Sill. Whole window 0.143 Btu/h·ft²·°F (R-7.0) with ZERO 04, 0.147 (R-6.8) with ZERO 05, at 600 × 1500 mm. Calculated
Modeled in LBNL THERM 8.1 at NFRC winter conditions, 0°F outside and 70°F inside. The red band on the room side shows the frame and glass staying close to room temperature; the lines are isotherms every 3°C (5.4°F).
Full engineering image ›All sections, ZERO 04 (PDF, 5.9 MB) ›ZERO 05 (PDF, 5.9 MB) ›Every section we model ›
Glass & glazing options
Standard glazing is the hybrid vacuum unit in one of six ZERO packages: three climates, each at two levels. ZERO 05 Daylight admits the most light and solar heat; ZERO 04 Ultimate has the lowest U-factor. For code-level projects, the double-glazed ZERO 24 packages are also available.
| Package | Center-of-glass U / R · SHGC · visible light |
| KØLD 05 · cold | 0.054 / R-18.5 · 0.49 · 76% |
| KØLD 04 · cold | 0.047 / R-21.1 · 0.35 · 64% |
| MILD 05 · mixed | 0.054 / R-18.6 · 0.35 · 67% |
| MILD 04 · mixed | 0.044 / R-22.6 · 0.27 · 53% |
| HEIT 05 · hot | 0.054 / R-18.6 · 0.26 · 61% |
| HEIT 04 · hot | 0.044 / R-23.0 · 0.20 · 45% |
| ZERO 24 KØLD · double glazed | 0.244 / R-4.1 · 0.57 · 83% |
| ZERO 24 MILD · double glazed | 0.241 / R-4.1 · 0.40 · 73% |
| ZERO 24 HEIT · double glazed | 0.242 / R-4.1 · 0.30 · 68% |
Quanex Super Spacer® Premium silicone-foam warm-edge spacer, argon-filled outer cavity.
Triple glazing, laminated and acoustic build-ups are also available to suit the project. Compare the ZERO packages ›
