Width of the overall glass unit is 1 3/8" top rating in energy efficiency.


Ostaco Windows and Doors Core PLUS - 1 

Core PLUS Construction:

  • Multi-chambered design adds insulation, sound abatement and strength.
  • Provision to add windbreak to cut down on air infiltration.
  • Groove for screen installation is inside the home.
  • Ostaco Windows and Doors Core PLUS - 2New Ostaco "inLighten" screen is available.
  • Accommodates a broad range of glass types and thicknesses including double and triple panes, highly energy efficient units or decorative glass.
  • Heavy-duty,multi-point locking system is standard to help secure your home.
  • Fusion-welded sash and frame corners prevent leaks, add strength and keep the window square.
  • Snap-in colonial glazing bead makes it easy to replace glass from inside your home.
  • Internal screw boxes and extra walls ensure sturdy hardware attachment.
  • The triple weather-stripping system provides a higher level of resistance to air and water infiltration.
  • Steel reinforcement available for larger size windows.
  • Interior groove to allow for the addition of mouldings such as 3/4" drywall return, wood jamb or all u-PVC jamb extension.
  • A wide range of decorative grilles and energy-smart glazing options are available to give your window a custom-designed look.
  • Provision for installation brackets.
  • Truth Encore Hardware is standard.

Core PLUS Casement/Awning Performance Ratings


Series Core Core Plus
Air Infiltration Resistance A3 A3
Water Infiltration Resistance B7 B7
Wind Load Resistance C5 C5
Forced Entry Resistance F10 F10


Core Series and Core Plus Series windows are Energy Star approved. Performance chart by USWADA.

Brochure download


Ostaco Windows and Doors Core PLUS - 3

Perfect for renovation and construction projects with 2x6 walls.  Because the frame of the window is 4 9/16" the sash sits closer  to the inside of the home providing a better insulating factor.



  • 4 9/16" frame


Frame Options

  • Available with a wide variety of wood extensions from pine to oak.




  • White, Ostaco Tan, Antique White (New), or exterior painted in your choice of colour.


Performance Rating

  • Energy Star approved.



Glass options

  • Standard Low E2;
  • our latest comfort technology LowE3;
  • or our new Low E 179c
    (the best ER rating in the entire world!).





  • A wide range of decorative grilles and energy-smart glazing options are available to give your window a custom-designed look.

Custom Fit

  • Every coreplus window is custom made to fit your homes exact specifications.  It can be a rectangular window, a curved window or even a round window