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How Much Do Bow & Bay Windows Cost?


Difference between bow and bay windows explained.

overhead bay window profileThe right type of a window, correctly designed and installed at a strategic location in your house can be that one thing that attracts you back home every day. Apart from offering amazing views, windows also help letting light and heat your house as well as making your home more aesthetically attractive.

Of all the various types and designs of windows that exist in the market, two among them merit a more in depth look and they are Bow and Bay windows.

If you are unfamiliar with the design, from a quick glance it’s understandable to not know which is which between these two types of windows due to their similarities.

Both windows project to the exterior of the house, giving more room from the interior. Both open up the room and let in more light into the house and can utilise vertical sliding sashes or even casements. However, there are significant differences between these two window types.

Bay Window Features

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Bay windows are usually found in a combination of three panels made up of one large window and two other smaller windows on the sides of the large one. Much like a “3-sided rectangle”, with the missing side being the interior of the room.

They jut out of the house forming a bay creating more space in the room. Bay windows shapes are normally square or rectangular with 2 sides and a front.

They protrude outwards from the main body of the house giving more floor space due to the fact that the bay is built floor-to-ceiling.

Due to the angular lines and flat panes of bay windows, they are appropriate and common in modern buildings though they are also found many older homes throughout the country.

New additions of bay windows to a house, need a bottom and a top. On upper floors this will mean creating a sufficiently supportive structure to take the weight of the bay.

Also the top of the bay needs to be protected from the elements by some kind of roofing. Unless the existing property roof extends far enough to cover the bay itself.

Ground level bay windows will also need a base and a roof. UPVC bay windows will need a less substantial base than one that incorporates brickwork pillars etc.

A popular feature of a bay window is to incorporate some kind of built in seating area in the bay, where you can sit and enjoy the light and the view.

Bow Window Features

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Bow windows, unlike the bay, are “curved” widow installation (hence the name bow), made up of more than three “side-by-side” windows joined at angles to form a graceful curve that gives a beautiful rounded appearance from the outside.

They have more glass panes than bay windows and can, as a result of the increased glazed area, allow more light in the house.

Strategically placed, bow windows can offer wide panorama-like views from all sides.

The bow window, unlike the bay, is simply a curved window used in place of a flat window and so does not typically extend from floor to ceiling. However, the bottom cill will project out form the building and need to be weather proof outside.

The top of a bay window is usually weather proofed outside by use of lead flashing.

The circular outer structure of bow windows is common in Victorian buildings but they are also employed in more modern houses.

Bow window overhead profile

How much do Bow Windows & Bay Windows Cost?

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The cost of bay and bow windows is largely dependent on the location and type of home as well as the owners’ preferences.

However, unlike normal flat windows, bow windows do not consist of a single window and hence are more expensive than a similarly sized flat window.

As a series of connected frames they need to be joined together accurately and fitted in such a manner that the unit does not move or “flex” causing damage over time. Also the bow has to be made weather-proof externally at the top & bottom.

Installation of bows & bays are more complex than that of flat windows hence the cost is going to be higher.

Of the two designs, bays are the more complex and costly to build from “scratch”. However, if you already have a bay window set in your home and just need to replace the windows and frames, then it would be a relatively simple matter.

Here are the average costs of Bay Windows & Bow Windows

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Bay Window DetailsMaterial Price Guide
  2500 x 1500 mm 3 panel Bay Window uPVC White£1,000 to £1,300
  3000 x 1500 mm 4 panel Bay Window uPVC White£1,400 to £1,700
  4000 x 1500 mm 5 panel Bay Window uPVC White£2.000 to £2,500

For coloured uPVC Bay Windows, you can add from 10% to 20% to the price


Bow Window DetailsMaterial Price Guide
 3500 x 3500 mm 5 panel Bay Window uPVC White £1,500 to £1,800
 3500 x 4000 mm  5 panel Bay Window uPVC White£1,800 to £2,000
 4000 x 4000 mm 5 panel Bay Window uPVC White£1,800 to £3,000

3 different types of Bow and Bay Windows 

William Henderson
William Henderson
William is a long time blogger for home improvement articles in the UK.