All replacement windows are custom to a point. They're built to fit specific openings, often in old houses that are wickedly out-of-whack. While most top-of-the-line manufacturers offer a wide range of specialty shapes, such as circle segments, elliptical tops, triangles, and trapezoids, there is also some leeway for customizing other elements. For example, Marvin provides a choice in sash sizes for most of its window lines: “Direct Glaze” products have a narrow frame that maximizes daylight, while the traditional “In-Sash” windows ensure that the glass edges of all geometrical topped windows align with other units. Similarly, Andersen offers a wide range of art glass options, including designs based on Frank Lloyd Wright's work. And Jeld-Wen offers hardwood, including mahogany, Pacific Coast red alder, and vertical-grain Douglas fir on the interior, and copper cladding for the exterior. However, even these options only go so far at the high end of the market or on an exacting restoration site.

Exacting Reproductions I recently walked a $5 million loft renovation in an old lower-Manhattan industrial building that needs replacements for the 15-foot-high, 10-foot-wide double-hungs. The customer wanted operable units and expected draft-free, energy-efficient performance. Nevermind that each lower sash would weigh well over 100 pounds once insulated, tempered glass units installed in copper-clad, mahogany sash were installed. None of that apparently was a problem. The architect had narrowed the list of prospective suppliers to three: Fenevations, Point Five Windows, and Zeluck (see “Resources” below).

That same afternoon, in a gut rehab of a brownstone in Prospect Park, Brooklyn, carpenter Michael O'Brien was considering the options for replacing three rectangular aluminum units cobbled together within the arched masonry openings of a round bay.

Chuck Bergerson, of Bergerson Cedar Windows, installs one of the traditional cedar double-hungs his company produces.
Chuck Bergerson, of Bergerson Cedar Windows, installs one of the traditional cedar double-hungs his company produces.

“Wouldn't it be great if someone still made double-hungs complete with sash weights like the originals,” O'Brien remarked. In fact, I had just learned about several companies that specialize in exacting reproductions of windows and doors: Jim Illingworth Millwork still relies on some milling machines dating from the 1890s to replicate doors and windows; Bergerson Cedar Windows specializes in traditional windows built from sustainably harvested cedar but will fabricate them from any wood specified; Grabill offers to replicate any window and maintains an art glass division that specializes in reproductions of beveled-, leaded-, and stained-glass panels.

The only things that have changed on these windows from their historic models are the accommodation of modern weather stripping, gaskets, and insulated glass panels.

An obvious difference between these and most replacement units is the cost. “Of course, sometimes price does get in the way,” admits Sue Illingworth of Jim Illingworth Millwork while describing several recent bids. “Everyone's got a budget, regardless of the scale.”

Resources This list is not exhaustive, but these companies can provide high-quality custom fenestration to architects and contractors nationwide. Once the bid — based on an accurate window schedule and project elevations — is accepted and the deposit received, they can develop complete shop drawings to verify every detail.

Bergerson Cedar Windows
Hammond, Ore.

Custom Trades International
Greenwich, Conn.

Kenilworth, N.J.

Grabill Inc.
Almont, Mich.

Jim Illingworth Millwork
Adams, N.Y.

Point Five Windows
Fort Collins, Colo.

Reilly WoodWorks
Calverton, N.Y.

Zeluck Inc.
Brooklyn, N.Y.