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

The Pella Impervia Series Fiberglass 2-Wide Casement Window delivers exceptional durability, energy efficiency, and a sleek, modern aesthetic. Made from Pella’s proprietary fiberglass, this window is designed to withstand extreme weather conditions without warping, cracking, or fading. With its strong frame, smooth operation, and customizable options, this window is an ideal choice for homeowners seeking both performance and style.

Frame

• Pella’s proprietary fiberglass is eight times stronger than vinyl.
• Resists warping, bending, and expanding in extreme temperatures.
• Slim, contemporary profile maximizes natural light.
• Low-maintenance material eliminates the need for painting or refinishing.

A strong, durable frame ensures long-lasting performance and a sleek, modern look without the maintenance concerns of wood or vinyl.

Sash

• Reinforced fiberglass sash enhances structural integrity.
• Hinged design allows for maximum ventilation and easy cleaning.
• Tight, secure fit improves energy efficiency and weather resistance.

A well-built sash provides smooth operation and enhanced energy efficiency, making it both functional and convenient.

Weatherstripping

• Multiple layers of weatherstripping minimize air and water infiltration.
• Helps maintain indoor comfort by reducing drafts and heat loss.
• Enhances energy efficiency for lower heating and cooling costs.

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

Glass

• Dual-pane insulating glass improves thermal performance.
• Optional triple-pane glass for enhanced energy efficiency.
• Low-E glass with argon gas fill helps reduce heat transfer and block harmful UV rays.

High-performance glass options offer superior insulation, reducing energy costs while protecting interiors from sun damage.

Interior / Exterior

• Interior and exterior finishes include long-lasting powder-coated colors.
• Resists fading, chalking, and peeling even in harsh climates.
• Sleek, modern design complements various architectural styles.

Durable finishes ensure a lasting, high-quality appearance without frequent maintenance.

Hardware

• Fold-away crank handle provides smooth operation and a clean look.
• Multi-point locking system enhances security and tightens the seal.
• Corrosion-resistant hardware ensures long-term durability.

Easy-to-use, secure hardware enhances both convenience and peace of mind for homeowners.

Screens

• High-transparency screens allow for improved airflow and visibility.
• Optional Pella InView™ screens provide 14% more light and 8% more airflow.
• Durable materials resist wear and tear for long-lasting performance.

Enjoy fresh air and clear views while keeping insects out with high-quality screen options.

Grilles

• Grilles-Between-the-Glass (GBG) for a low-maintenance, stylish look.
• Available in 5/8" flat or 1" contoured styles.
• Choose from Traditional, Prairie, and Custom grille patterns.

Grilles add character and charm while maintaining an easy-to-clean, modern window design.