Innovative Products: Sierra Pacific H3 High-Performance Windows

The frame of Sierra Pacific Windows’ H3 Window uses three materials—vinyl sandwiched between wood and aluminum—to create a nearly perfect thermal break and excellent overall energy performance. Dubbed “Fusion Technology,” the core of the system is a heavy (0.072 inch) vinyl frame that accepts solid wood sashes clad on the exterior with heavy-duty extruded aluminum that the company says is twice as thick as standard roll-formed cladding. 

A unique “snap-lock” system connects the vinyl to both the aluminum cladding on the exterior and the solid wood extension jambs and stops on the interior, hiding the vinyl channel and minimizing the number of visible fastener holes that need to be filled.

The Transcend line of H3 insert windows is designed to fit between existing jambs without disturbing interior trim, and can be sized in ⅛-inch increments with jamb depths up to 5 ⅛ inches. Operable models include casements, awnings, and tilt-in double-hung units. 

New-construction units, which also include sliders and fixed-glass (picture and transom) options, have a rigid integral nailing fin that helps eliminate racking problems during installation and provides a convenient surface for sealing a water barrier. The windows can be ordered in custom sizes and with jamb depths up to 8 ⅛ inches. Multiple units are shipped with continuous head jambs and sills, eliminating the need for field mulling.

H3 windows are double- or triple-glazed with numerous high-performance coating options, including Cardinal’s Low-E 366, which reduces solar heat gain while preserving visible light transmittance, and Low-E 180, which allows passive solar gain while reducing heat loss.

Divided lites can be simulated either with surface-mounted exterior and interior bars (with or without aluminum between-the-glass spacers) that match cladding and wood species, or by between-the-glass grilles in three profiles: ⅝-inch flat, or 11/16- or 1-inch contour. Two-tone grilles are also available.

Interior wood—including all 13 optional trim styles—is available in 9 species that can be factory finished in three stain colors (Clear, Espresso, and Toffee) or with a two-part catalyzed polyurethane white paint. Aluminum cladding is available in five extra-durable anodized finishes and in 70 powder-coated finishes that meet the AAMA 2605 organic coating standard (custom color matching is also available). 

We spoke with Michael Anschel, owner of Otagawa-Anschel Design + Build, in Minneapolis, who used triple-glazed H3 windows throughout a recent whole-house remodel. Anschel says he got more window than he bargained for. “The almost completely thermally broken vinyl frame makes the window lighter in weight, but you still have the beauty of wood on the inside and aluminum cladding on the outside.” 

This, along with glazing options and a high-quality foam spacer, is an important element in the window’s performance. “Condensation resistance [CR] really attracted me to this window,” Anschel says. “The H3’s CR 69 exceeds the ideal CR 65 listed on the NFRC label.” 

Plus, Anschel likes the way the window looks: “The narrow glazing-to-frame dimension and abbreviated reveals means there’s less in your way visually.”