Pella Impervia mulled casement windows combine three same-sized units for easy installation. Each fiberglass window sash swings outward away from the home.

The Pella Impervia Fiberglass 3-Wide Casement Window offers exceptional durability and modern performance with a sleek, contemporary design. Made from Pella’s proprietary fiberglass, this window resists warping, cracking, and expanding, ensuring long-lasting reliability in any climate. With three casement panels that open outward, this window provides excellent ventilation, energy efficiency, and an expansive view of the outdoors.

Frame

• Constructed from Pella’s proprietary fiberglass, which is eight times stronger than vinyl.
• Resists warping, swelling, and damage from extreme temperatures and moisture.
• Narrow frame design maximizes natural light and enhances modern aesthetics.
• Low-maintenance finish resists fading, chalking, and peeling.

A strong and stylish fiberglass frame ensures lasting performance with minimal upkeep, making it a smart investment for any home.

Sash

• Reinforced fiberglass sash provides extra strength and durability.
• Opens outward for optimal ventilation and easy cleaning from the inside.
• Multi-lock system secures the sash tightly for improved energy efficiency and security.

The durable sash design enhances ease of use while ensuring a secure and energy-efficient seal when closed.

Weatherstripping

• Dual weatherstripping provides a tight seal to reduce air and water infiltration.
• Helps maintain indoor comfort by preventing drafts.
• Improves overall energy efficiency for reduced heating and cooling costs.

Reliable weatherstripping keeps your home comfortable while reducing energy expenses year-round.

Glass

• Dual-pane glass with optional triple-pane upgrade for enhanced insulation.
• Low-E glass with argon gas fill minimizes heat transfer and UV exposure.
• Impact-resistant glass options available for added durability and security.

Advanced glass technology helps regulate indoor temperatures, lower energy bills, and protect furnishings from sun damage.

Interior / Exterior

• Powder-coated interior and exterior finishes resist fading, peeling, and chalking.
• Available in a range of modern, low-maintenance color options.
• Designed to complement both contemporary and traditional home styles.

A durable and stylish finish ensures a long-lasting, attractive appearance with minimal upkeep.

Hardware

• Multi-point locking system enhances security and weather resistance.
• Smooth, easy-to-use crank handle for effortless operation.
• Corrosion-resistant hardware designed for long-term durability.

Premium hardware ensures a secure, reliable, and user-friendly window operation.

Screens

• High-transparency screens improve airflow and visibility.
• Optional Pella InView™ screens allow more light and airflow than standard screens.
• Durable screen materials resist wear and tear for long-lasting performance.

Enjoy fresh air and clear views with high-quality screens designed to keep insects out without blocking natural light.

Grilles

• Grilles-Between-the-Glass (GBG) for a sleek, easy-to-clean appearance.
• Available in 5/8" flat or 1" contoured styles.
• Choose from Traditional, Prairie, and Custom grille patterns.

Stylish grille options allow homeowners to customize their window’s appearance while maintaining easy maintenance.