Pella® Impervia® Fiberglass Single-Hung Window

Mulled

Pella Impervia mulled single-hung windows include two units joined by their frames in the factory. This doubles the size of a single unit, creating a more expansive look. Made from the strongest material for windows, Pella’s exclusive fiberglass provides lasting durability and sleek, timeless style.¹⁶ Single-hung windows have a moveable bottom sash for ventilation with a top sash that remains fixed. Achieve your design vision with a variety of popular features and options to choose from.

Two fiberglass single-hung windows mulled together as a combined unit.
Fiberglass material is tested beyond industry standards to perform from -40ºF to 180ºF.
Equal sightlines deliver a clean, consistent aesthetic unlike other single-hung designs that trade off aesthetic details.

Product #401002

Configuration: 2-wide

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Design Options

Solid-Color Frames

Black
Brown
White
Morning Sky Gray
Tan

Frequently Asked Questions

Frame	Overall frame depth is 3". Frame corners are mitered, joined and bonded with corner lock and mechanically fastened with injected polyurethane adhesive. Sill is fitted with weep valve assemblies.
Sash	Sash is Duracast fiberglass composite – five-layer pultruded fiberglass material reinforced with a Pella patented interlocking mat. All sash members have mitered corners bonded with corner lock and sealed with injected polyurethane adhesive.
Weatherstripping	Sash is weatherstripped around the perimeter with a dual fin-type pile weatherstrip.

Glazing System	Quality float glass complying with ASTM C 1036. 11/16" insulating glass sealed and bonded to sash. High altitude glazing available.
Hardware	Optional limited opening device available for field installation on vent units in vinyl to match interior of unit; nominal 3-3/4" opening. Optional window opening control device available for field installation. Device allows window to open less than 4" with normal operation, with a release mechanism that allows the sash to open completely. Complies with ASTM F2090-10.
Screens	Half-size with black vinyl coated 18/16 mesh fiberglass screen cloth complying with ASTM D 3656 and SMA 1201. InView™ Screen - Half-size with black vinyl coated 18/18 mesh fiberglass screen cloth complying with SMA 1201. Set in aluminum frame and fitted to outside of window.