Choose the ESP = Energy Saver Package for in dual pane glass for the  enegry saving performace you need. The Insul-Tec 500 will deliver not only a beautiful look but stand up to the test of time. Okna windows are know as a great value when considering replacement windows. Call us today and we'll help you make an intellegent decision.

  • 10% Better than Energy Star® minimum
  • 333% Better Air Infiltration protection than Industry Standards.
  • 3¾" Depth Welded Mainframe with superior strength long lasting performance.
  • The Heatseal® warm edge spacer system provides excellent thermal efficiency 
  • Full integral interlock with double weather-stripping.
  • Optional Auto-Locking system
  • Heavy gauge fully extruded handles 
  • Factory installed Fiberglass mesh half screens come standard on all windows
  • Great for Replacement and New Construction applications
  • Available in 2-lite and 3-lite choices
  • Available grids between glass in Common Grid Patterns
          Energy Star Comparison To
Glazing Option U-Value SHGC VT CR Minimum* Energy Star Minimum
Dual Glazed              
With ESP 0.27 0.30 0.54 62 0.30 10% Better


      Industry Comparison To  
  OKNA Windows Minimum Industry Minimum  
AAMA Rating  R40 R15      
Air Infiltration cfm/ft2 0.09  0.3 333% Better
Water Penetration mph    59  33   79% Better  
Structural Integrity mph  153  94   63% Better