PERFORMANCE outward opening casement window

Triple glazed timber outward opening casement window with U value as low as 0.85 W/m2K. Cost-effective option for low energy retrofits and newbuilds.


  • Outward opening (inward opening also available)
  • High performance triple glazing
  • FSC® redwood or oak timber
  • Secured by Design option
  • 78mm profile
  • BRE Green Guide A+
  • Made exclusively for Green Building Store by our partners in northern Europe

Glazing & U values

Whole window U value: Uw 0.85 W/m2K (Redwood)
Whole window U value: Uw 0.93 W/m2K (Oak)
Glazing Ug: 0.58 W/m2K
Triple unit: Argon fill 44 mm
Light transmission value: 74.1%


Typical maximum sizes
Fixed light: 2500 mm X 2500 mm
Side hung: 950 mm X 1520 mm
Top hung: 1300 mm X 1650 mm

Please see some sample styles below. If you can’t see the style you’re looking for, please get in touch, as everything we do is bespoke and made to your requirements.

Provided by NBS

Affiliations & Accreditations