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OKNA 820 Performance - Sliding Windows

We stand firmly behind the quality of all OKNA 820 Series windows we install, and would easily compare them to premium brand windows costing two to three times as much.   Our 820 Wonder Choice windows have become increasingly popular in the past few years, due to their stylish appearance, reliable weather resistance, leading energy efficiency and overall value.

OKNA 820 Sliding Window

OKNA 820 Series

  • Perfect as replacement windows or in new construction projects
  • Carefully designed to work with almost any room or motif 
  • Includes standard half-screen made from premium fitted mesh
  • Automatic moisture and condensation prevention feature
  • Powerful 3.25" fusion-welded mainframe construction
  • Colonial inspired curves and bevels uniting strength and beauty
  • Designed to provide years of consistently-reliable performance
  • Multi-chambered vinyl profile for maintenance-free use
  • 820 Series windows utilize Heatseal® for improved efficiency 
  • Interlocking double-insulated weather stripping
  • Increased window security with a locking screen upgrade.*
Overview - Options & Accessories - Performance

Performance Options Available - EnviroStar

          Energy Star Comparison To
Glazing Option U-Value SHGC VT CR Minimum* Energy Star Minimum
Dual Glazed            
with ESP 0.28 0.28 0.52 63 0.30 7% Better than ENERGYSTAR®
Deluxe 0.26 0.28 0.52 63 0.30 13% Better
Triple Glazed            
with ESP 0.22 0.25 0.41 73 0.30 27% Better
Deluxe 0.20 0.25 0.41 73 0.30 33% Better than ENERGYSTAR®
Deluxe w/krypton 0.16 0.25 0.41 75 0.30 47% Better than ENERGYSTAR®
U-Value, SHGC, VT, CR values may slightly change for windows made with GBG (Grids Between Glass)
  • SHGC - Solar Heat Gain Coefficient
  • VT - Visible Transmittance
  • CR - Condensation Resistance
  • Deluxe - ESP & Foam
  • * Northern Climate Zone
**   Industry Comparison To
  Our Windows Minimum Industry Minimum
AAMA Rating (38 x 63) R50 R15  
Air Infiltration cfm/ft2 0.05 0.3 600% Better than ENERGYSTAR®
Water Penetration mph 62 33 88% Better than ENERGYSTAR®
Structural Integrity mph 171 94 82% Better than ENERGYSTAR®

Water Penetration mph - Specifies wind load pressure in mph a window can withstand without leaking, under rain equivalent to 8" per hour. Structural Integrity mph - Wind load in mph a window can withstand before breaking.

All results numbers are based on tested window sample by NFRC & AAMA testing window guidelines. Use for comparison purposes only. Actual values may vary depending on installation, size of the window, and other conditions.