Bay and Bow Windows extend beyond the wall to create a light-filled nook and a dramatic focal point inside and out. A bay combines a large center pane with two angled sides; a bow uses a gentle curve of four or more panes.
They’re a signature upgrade for living rooms, kitchens, and primary suites — and the projected sill makes a perfect reading seat or display ledge.
Everything a Bay or Bow Window unit is — the projection, the seat, the sweep of the view — is decided by the design and frame before a pane of glass goes in it. That custom-built frame is installed to your opening and arrives in one piece. What follows is one window unit on one house — the same Bow, Window unit from the driveway to the finished trim.
Four windows on a shallow arc, built exactly to within 1/8 of an inch to this opening and delivered in one piece. It arrives at your home already in the shape it will keep.
The old window out, the opening squared, and the frame lifted up to it. A Bow this wide is a four-person job off two ladders.
Two windows installed and two to go. Leveled, fixed to the framing and totally weather-sealed the whole way around before any film comes off.
The same Bow Window unit with the film off and the glass cleaned — exterior black capping, sill and head board finished, inside and from the garden.
Curtains up, plants along the sill, casements cranked open. The same window a few weeks on performing exactly what it was purchased for.
That unit went into an opening that was already there. See what happens when there is no opening yet — one Hat Box Bay cut into a second-floor wall, headed and hung, photographed over two days.
All of them project past the wall and all of them give you a sill. What separates them is how many times the frame turns on the way round, and how sharply — which decides the shelf inside, the roof above and the line the house shows the street.
A flat center light with an angled return either side. It turns twice, projects squarer than a Bow, and leaves the deeper sill of the two.
Four or more equal lights, turning a little at every mullion so the wall curves rather than folds. The most glass of any of them.
Two lights meeting at a point. No center pane at all — the frame turns once, in the middle, and comes back to the wall. More on two lite V Bays.
Square returns instead of angled. The deepest shelf of the set, and the most head and roof to build above it.
The same box, with the frame carried out past it at both ends and glazed there too. A window in each ear as well as across the front. More on hat box Bays.
The shallowest of the set. A square projection and a sill, without the depth — or the roof and header work — of a full Box Bay. More on Bump Out Bays.
The projection brings in light from multiple angles and adds floor space.
The deep sill becomes a window seat or display ledge.
A striking architectural feature from the street.
Every unit is built to the opening, so these are the ranges rather than a list of stock sizes. If your wall falls between two of them, that is what the free measure is for.
A flat center with two angled returns.
Square returns — a Box Bay, deepest shelf of the three.
Four or more equal lights on a shallow arc.
180″ is 15 feet, and 26″ is a little over two — the range covers a whole living-room wall down to a single deep nook. Heights run to 77″ across all three.
$4,000 to $35,000, supplied and installed.
That is a wide range and it is meant to be. A custom Bay or Bow Window unit is built to your exact opening rather than picked off a shelf, so four things move these numbers more than anything else:
No window company can price a Bay or Bow Window project properly without seeing the opening. An in-home conversation with one of our Project Designers is free and you are given the estimate in writing.
A Bay uses a larger flat center window with two angled returns, so it projects squarer and leaves a deeper sill. A Bow carries four or more equal lights on a shallow arc, so the wall turns gradually and the glass sweeps round. Both push out beyond the wall; the Bay gives you more shelf, the Bow gives you more curve and more glass.
Bay and Bow Window units typically start around $4,000 and can reach $35,000 supplied and installed. The spread is wide because these are built to the opening: width and the number of lights, whether it replaces an existing projection or opens up a flat wall, the glass specified, and how the head, roof and interior seat are finished all move the number. You get an exact figure in writing after the in-home measure.
The unit itself usually goes in within a day. The five steps on this page are one window on one house, from the frame arriving on the driveway to the trim finished. An opening that has to be widened, headed or re-roofed takes longer, and we tell you which of those you are looking at before the work is booked.
Replacing a Bay or Bow with another one usually does not — the opening and its header are already carrying the load. Turning a flat window into one that projects usually does: the opening is widened, a header sized and fitted, and the projection needs its own roof or head board with the seat supported beneath it. Which of the two you are looking at is settled at the measure, not on site halfway through. Where a load-bearing wall is being opened, the header is not sized by eye: a structural engineer draws it, the drawings go to your municipality for approval, and the beam that goes in is the one on the approved drawing.
If the wall carries load and the opening is being changed, yes — and it is our job, not yours. A structural engineer draws the header, the drawings are submitted to your municipality, and the work is inspected. Swapping a Bay for a Bay in an opening that already exists is usually a different matter. We tell you which one you are looking at before you commit to anything.
It depends on the unit. A Bay projects further than a Bow of the same width because it turns at two sharper angles, so a Bay gives the deeper shelf and a Bow the longer one — the Bow on this page seats the full width of the opening. Because the frame is built to your opening, the projection and seat depth are quoted for your window rather than taken off a chart.
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