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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.

OKNA 520 Sliding WindowEnhance your window with stainless steel, brass or bronze handles and locking mechanisms.

  • Ideal for both replacement windows and new home construction
  • Dual-layered insulation interlocks tightly for enhanced efficiency
  • Designed to work universally with a broad scope of hardware
  • Innovative condensation and draft-prevention technology
  • Thermal efficiency enhanced by patented Heatseal® spacer
  • Renowned for its chambered maintenance-free vinyl design
  • Rugged 3.25" deep-welded frame for exceptional durability
  • Increased security with locking screens and enhanced locks
  • Comes standard with high-quality fiberglass mesh half-screen
  • Specially designed to withstand harsh WNY weather conditions
  • Our company offers 2-lite and 3-lite (shown) sliding windows.

  • Full 3¼" Depth Welded Mainframe with beveled colonial exterior features curves that are not only beautiful, but also allow for maximum weld surface resulting in strength and years of long lasting performance.

  • Our window opens easily because it is mounted on brass wheels which allow the slider to smoothly glide across its track.

  • Push Button Spring-Loaded Vent Latches allow both window sashes to remain partially open for ventilation.


Interior Options

Our company offers two interior colors in addition to our standard Euro-White to give your home a distinct look.

Optional colors are available at additional cost.



Exterior Options

Okna Windows offers six exterior stock color selections in addition to the standard Euro-White option to give your house a distinct look and enhance its curb appeal. You can also select custom exterior colors from a virtually unlimited selection of paints. Our paints are environmentally safe and durable, giving your exterior a vibrant and long-lasting color finish.



Terra Brown


Basic Brown


Nicol's Black

Custom Colors


To create a style and finish that reflects your unique taste, our hardware is designed to harmonize with our different window styles and decor ideas.





GBG grilles consist of aluminum bars sealed in the insulation airspace between the two panes of glass. Because the interior and exterior glass surfaces are not affected, cleaning your windows is a much easier task.

Permanent interior and exterior grids with spacer will provide a truly authentic look. Interior grids are available in Euro-White or wood laminates to match your home's decor. External grids are available in Euro-White or colors to match product exterior.

Flat Grid

Contour Grid

Grid Patterns

Are you looking for a stunning design detail to instantly set your home apart both inside and out? A choice of decorative grilles for your Okna Windows & Doors can highlight the architectural style that speaks to you.




Glass Options

Okna Windows offers textured glass in a variety of distinctive choices that add visual interest to any design while offering variability in light control. With a range of options at your fingertips, you can find a standard glass texture for virtually every application and aesthetic, from traditional to modern.

Obscure Glass

Niagara Glass


Okna Windows offers factory-installed half screen with heavy-duty handle. Screens are removable from the inside for convenient storage. We also offer ThruVision Screens improving view thru the window protecting interior from insects and allowing perfect ventilation.

ThruVision Plus is our fiber glass improved visibility screen. This product does for windows and doors what high-definition technology has done for television viewing; it improves the view by making it sharper and more vivid.

Industry Average Screen

ThruVision Plus Screen

Series OKNA Insul-Tec 500 Series OKNA Insul-Tec 500 Series
Triple Pane Standard Standard
Double Pane Optional Optional
Model Name Super Deluxe Deluxe
Glass Panes Triple Pane Double Pane
U-Factor 0.20 0.26
Solar Heat Gain (SHGC) 0.26 0.30
Visible Transmittance 0.42 0.54
Condensation Resistance 72 63
Design Pressure DP40 DP40
Structural Performance R40 R40
Air Infiltration 0.09 0.09
Foam-Filled Frames Yes Yes
Screen ThruVision PLUS ThruVision PLUS
Manufacturer's Warranty Lifetime Lifetime
Our Labor Warranty Lifetime Lifetime
Glass Breakage Free Free
ENERGY STAR Most Efficient Yes* Yes*

*with triple pane glass

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

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