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OKNA 520 Performance - Sliding Windows

In addition to being one of the most popular replacement windows here at Wonder Windows, the OKNA 520 Series window has features commonly found on more expensive designer windows.  They've soared in popularity in the past decade, and are a popular favorite here in Rochester. Artisan-inspired craftsmanship, coupled with distinct lines and a neutral design style, the 520 Series is ideal for those seeking a perfect balance of energy efficiency, low maintenance and traditionally modern design.  Enhance your window with stainless steel, brass or bronze handles and locking mechanisms.

Overview - Options & Accessories - Performance

Performance Options Available - Insul-Tec

          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 than ENERGYSTAR®
Deluxe 0.26 0.30 0.54 62 0.30 13% Better
Triple Glazed            
with ESP 0.21 0.26 0.42 70 0.30 30% Better than ENERGYSTAR®
Deluxe 0.20 0.26 0.42 71 0.30 33% Better
Deluxe w/krypton 0.16 0.26 0.42 74 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) R40 R15  
Air Infiltration cfm/ft2 0.09 0.3 333% Better than ENERGYSTAR®
Water Penetration mph 59 33 79% Better than ENERGYSTAR®
Structural Integrity mph 153 94 63% 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.