Bow Windows

A bow window uses four to six units set at shallow angles to form a curve. A bay window uses three units at sharper angles to form a faceted projection. Bows are wider and shallower, bays are narrower and project further into the room. Bows cost more because there are more units to build, join, and seal.

A bow window costs more than a bay of similar width, because it uses more individual units and more mullions and the projecting roof is longer. The Norden Seal installed price ranges by size are listed in the table on this page. A four-panel bow costs meaningfully less than a six-panel.

Four, five, or six. Five is the most common residential configuration. Fewer than four units is a bay rather than a bow, and more than six is unusual on a house and starts to require intermediate structural support.

Most do, partially. A typical bow has fixed units at the centre and operating casements at one or both ends. You can also specify all-fixed for pure view, or alternate fixed and operating units across the curve. Casements are the usual operating choice because they seal better than sliders on an angled unit.

Yes, but it is structural work rather than a window swap. Converting a flat opening to a bow means widening the opening, installing a new header, building a projecting floor and roof, and flashing the whole assembly into the wall. It needs a permit. Replacing an existing bow with a new bow is far simpler, provided the supporting structure is sound.

The glass units themselves are as efficient as any other Norden Seal window, with the same Low-E, argon, and warm-edge spacer options. The weak point on a bow is the assembly around the glass: the seat, head, and roof cavities. If those are properly insulated and air-sealed the bow performs like the wall it replaced. If they are not, the bow becomes the cold spot in the room.