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Pella® Impervia® Fiberglass Casement Window


Pella Impervia casement windows open and close with the turn of a crank. Create sleek designs featuring slim profiles and more visible glass with our exceptionally strong fiberglass. And with a durable powder-coat finish, Pella Impervia casement windows deliver a timeless, long-lasting look.

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Impervia Casement Window Features

Why Fiberglass?

  • Superior strength and durability with patented fiberglass material16
  • Withstands the most extreme temperatures
  • Long-lasting powder-coat finish, including Black
  • Sleek, slim profiles
  • Meets the rigorous performance requirements of a commercial building43

Performance Enhancements

  • Optional foam insulation for better energy performance
  • Exceptional energy efficiency
  • Innovative locking system for improved security and a stronger seal
  • Patented unison locking system, with one easy-to-use lock-lever

50% off qualifying installations1,3or0% APR for 48 months2,3

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Inside Pella Impervia

Made from our patented five-layer fiberglass material, Pella Impervia windows are on average 100x more impact-resistant than a leading wood/plastic composite product.59 Tested from -40ºF to 180ºF, these windows can withstand some of the harshest conditions, making them strong and incredibly energy efficient.16

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For the Pros

Pella Impervia Casement Window Specs & Install Details

  • Unmatched strength and lasting durability for proven performance and sleek style
  • Tested and designed for the extremes
  • Operable casement windows available in sizes up to 37-1/2” x 79-1/2”
  • Fixed casement windows available in sizes up to 71-1/2” x 79-1/2”
  • Performance class and grade LC40-LC50
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Options for Pella Impervia Casement Windows

Choosing Your Window


Make a design statement with window combinations. Additional combinations are available. See your Pella sales representative for the complete offering.

Interior Finishes

Pella Impervia fiberglass products have a long-lasting factory powder-coat finish in your choice of five colors plus dual-color frame options. Learn more about interior finishes.


For Pros

  • Pella Impervia windows are made from Pella's patented five-layer, engineered Duracast® fiberglass composite.
  • A fiberglass composite sharing the same properties of strength, durability and temperature resistance as materials used in the aerospace industry.
  • Allows Pella Impervia products to withstand extreme conditions better than windows made from other materials.
  • Highly stable material won't expand, warp or sag in summer heat, or shrink and turn brittle in harsh winter conditions.

Styling Your Window


Pella's fold-away crank is available in today's most popular finishes.


For Pros

These windows are available with a range of hardware options and finishes to meet most design objectives and budgetary requirements.

  • Integrated crank with fold-away handle.
  • Patented Unison Locking System.
  • Stainless-steel operating arms and hinges.
  • Optional limited opening and egress hardware.
  • Color-matched or optional finishes.

Grille Patterns

Grilles give the appearance of individual window panes. Pella offers many grille patterns to help enhance your home's architectural style.


Grille Profiles

Grilles-between-the-glass create the classic look of individual windowpanes. Learn more about grille profiles.

3/4" Grilles-Between-the-Glass


  • Aluminum grilles with 3/4" contour are permanently sealed between the panes of insulating glass.
  • Finish is color-matched to interior and exterior frame color.
cross section of dual-pane grilles between the glass

Dual-Pane Grilles-Between-the-Glass

Window Enhancements

Integrated Security Sensors

Stay connected to your windows.

Preserve beauty, add comfort and enhance home security with innovative Pella Insynctive® technology.

Protect what matters most. Monitor windows while at home or away with the Pella Insynctive App.40

insynctive app in hand with status


Conventional Fiberglass Screens

Pella's high-transparency screens are made of a finer screen fabric than conventional screens for a clear view that allows more air and natural light to flow into your home.

Pella InView™ screens let in 14% more light and are 8% more open for improved airflow compared to conventional fiberglass screens.5

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Pella products are backed by some of the strongest warranties in the business.

Learn more about Pella warranties

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