Our 1920s colonial has an old bay with a copper roof. Can the roof stay when the windows are replaced?

Often, yes. Manufacturer instructions treat the unit's head board as a temporary cover and expect the roof above to be self-supporting and weather resistant, so a sound, independently framed roof can stay. Cost guides price a same-opening bay swap at about $1,800 to $2,500. Ask the installer to check the roof framing and flashing before quoting, and to say in writing whether the roof is in the price.

For a narrow front room in a two-family house, is a bow or a three-panel bay the better fit?

It depends on wall width and airflow. A bow spreads 4 to 6 or more panes across a shallow curve and is often mostly fixed glass, so it is usually larger than a bay and opens less. A three-panel bay usually has a fixed center with two opening flankers. Cost guides put bays at $2,000 to $6,000 and bows at $3,000 to $8,000.

Will a new bay make our living room colder in a Lowell winter?

Not if the glass and the seal are right. Cost guides call a bay energy efficient when it has double- or triple-pane low-E glass and is sealed properly; install instructions call for backer rod outside and low-expansion foam around the whole perimeter inside. Ask that the glass meets the energy code U-factor, and look under the seat board for insulation.

Can a garden window go over the kitchen sink where a flat window is now?

Yes, and over a sink is where most of them go. Garden windows there are typically about 24 by 24 inches and run around $700 to $1,000 installed in national data. A new installation takes 1 to 2 days, a replacement less because the opening and support are already there. Widening the opening is a bigger job that needs reframing.

How long is the room open to the weather during a bay swap?

Usually less than a day for a straight replacement. Cost guides put an existing-bay swap at 1.5 to 2 hours per window section and a picture-to-bay conversion at 6 hours to 2 days. Cutting a new opening in a wall takes 1 to 4 days, and the roof over the projection still has to be finished after the window is set.

Bay & Bow Windows in Lowell, MA

Standard three-panel bay: national cost guides put most at $2,000 to $6,000 installed.
Bow window (4 to 6+ panes): usually $3,000 to $8,000 installed, the largest units at the top.
Swapping an existing bay in its opening: about $1,800 to $2,500 for labor and materials.
New roof over the projection: roughly $1,800 to $4,600 or more, shingles low, copper high.
Time on site: 6 hours to 2 days to turn a picture window into a bay; 1 to 4 days when a wall is opened.

Lowell Window Replacement puts you in touch with a local window company for bay, bow and kitchen garden windows, whether the old unit comes out of the same opening or a flat wall gets a new projection. The referral is free to you; the measurements, the quote and the contract come from the installer.

Bay and Bow Window Types for Lowell Homes

Three-panel angled bay window with a center picture window and two double-hung flankers on a white clapboard colonial in autumn

30- and 45-Degree Bay Windows

A standard bay has three sections: a wide center picture window and two narrower side units set at 30 or 45 degrees to the wall. The flankers can be fixed, or they can open as double-hung or casement windows, which is where most of the ventilation comes from. Cost guides price an angled (canted) bay at $1,800 to $6,000 installed, and split bays by size:

Small or basic: $800 to $2,500
Midrange or standard: $2,000 to $6,000
Large or custom: $3,500 to $8,000

Five-panel curved bow window on a gray shingled cape-style house under a light winter snow, warm light inside

Four- to Six-Unit Bow Windows

A bow uses 4 to 6 or more equal panes set at shallower angles, so it reads as a gentle curve rather than three flat faces. Many bows are mostly fixed glass, which gives the widest view and the least airflow. Expect $3,000 to $8,000 installed in national data. Repair math matters here: fixing a failing bow with four or more panes runs about $1,200 to $3,200, and labor alone on a large bow or bay can reach $800, so an older bow with several failed units is often a replacement quote rather than a repair.

Small kitchen garden window projecting over a white farmhouse sink, potted herbs on the glass shelf, morning light

Kitchen Garden (Box-Bay) Windows

A garden window is a small box bay: a flat front with side panels at 90 degrees and a shelf deep enough for plants. Most go over a kitchen sink.

24 x 24 in (typical over a sink): $700 to $1,000 installed
36 x 36 in: $1,000 to $3,000
Large living-room units up to 60 x 72 in: $2,500 to $6,000
Split: $700 to $3,000 for the unit, $300 to $1,000 for labor and supplies
Time: 1 to 2 days for a new installation; less for a replacement

Underside of a vinyl bay window seat board with steel support cables running up to the wall above, siding partly removed

Roof Cap, Seat Board and Support Cables on a Bay Replacement

A bay hangs off the wall, so its structure is part of the quote. In one manufacturer's instructions, support cables run from a structural member above the opening down through the unit to threaded rods under the seat board, and turning nuts on those rods levels the seat. The seat and head boards are fastened into the framing at no more than 16 inches on center. The same instructions say the head board is not a finished roof: it needs a self-supporting, weather-resistant roof built over it right away. The Massachusetts residential code lists Lowell's ground snow load at 50 pounds per square foot, so a bay roof here carries real winter weight. A new roof for the projection costs about $1,800 to $4,600 or more, with half-octagon and three-sided hip shapes the usual choices.

Installer seen from behind pressing a new white double-hung window into an old painted wood frame, with a level on the sill and shims and a caulk gun on a drop cloth

Why Lowell homeowners call Lowell Window Replacement

One independent window contractor gets your request
Ask for the HIC number: MA contracts must show it
Written contract on any job over $1,000
The call and the referral are free

Bay Window Cost in Lowell: What Moves the Price

National guides give the ranges below; the written quote is what counts for your house.

Vinyl frame
$700 to $3,500 installed
Fiberglass frame
$900 to $4,500
Wood frame
$1,100 to $6,000
Low-E double- or triple-pane glass
adds 10% to 25% to material cost
Labor
$500 to $2,500, highest when a new opening is cut
New-opening extras
siding repair $200 to $1,100; drywall repair $300 to $1,500 or more
Window seat and trim carpentry
$30 to $200 per hour

The biggest split is same opening versus new opening. A replacement that reuses the opening, the support and the roof stays near the low end. Turning a flat window into a bay means reframing, a building permit, and outside work on siding and roofing.

Bay Window Replacement on Older Lowell Houses

On the city's older houses, many bays are original wood units with their own small roofs. Some are oriels: upper-floor bays that never reach the ground and hang on corbels or brackets, priced at about $1,500 to $5,000 in national guides. Ask whether staging is needed to reach one and whether it is priced in. Before you sign:

Seat and support
Ask the installer to look under the seat platform and at whatever holds the bay up (brackets, knee braces or cables) and to say whether it stays or gets rebuilt.
Roof and flashing
Ask whether the existing roof is reused, re-flashed or replaced, and get that line priced on its own.
Glass
The new units should meet the energy code U-factor for Massachusetts.
Paint
Pre-1978 houses need lead-safe work when old painted trim is cut out.
Historic district
A bay on a street-facing wall downtown may need Historic Board review first.
Payment
Get a written contract and keep the deposit within the legal cap.