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Bow Windows and Bay Windows

Bow Windows and Bay Windows

Bow windows Vs Bay windows – how much do they cost?

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Bow Windows and Bay WindowsIf you are looking at options to add a new picture window or upgrade an existing one to boost your homes’ appeal or increase the functional area of your living room, then you would, in all probability, be considering bow window or bay windows.

Although both are projecting “picture” window systems, they are different from each other. However, the differences are worth clarifying to avoid any potential confusion.

What benefits do Bow or Bay Windows have to offer?

Although bay windows, bow windows serve the same purpose, they are still different from each other. While both the window types protrude from your home’s exterior and can sometimes look somewhat similar, on a closer inspection, you will be able to identify the differences.

bay window seatA Bay window has three sides, left, right & front.

A Bow window has one curved side, usually a set of 5-6 widow units’ side by side to from the curved shape

The central panel in the Bay window system is fixed and is called a picture window. It is usually the largest of the three windows with the side windows flanking it from both sides.

In a Bow window, all the window panels are of equal size. While the top portion of both the window types is curved, the degree of curvature varies.

The arc of a Bow window gives a curved, symmetrical appearance from the exterior whereas there are usually no curves present in a Bay window giving it a flat planed look.

Having said that, Bay windows do not have to have the sides set at right angles to each other that can be set at angles bigger that 90 degrees to give a less rectangular appearance.

Both Bay & Bow windows can extend from floor to ceiling. But in most cases a bow window will effectively be a curved version of a standard window, whilst the bay window is normally the design that runs from floor to ceiling.

What is the difference between how a bay window and a bow window look?

As seen from above in profile,is it easy to spot the differences between bow & bay windows.bow window profile

The basic underlying window structure of both these window styles drive the benefits that you can get from them.

Since both the windows extend from the main body of the house you get added room space.  However, in order to really take advantage of this feature you would need to install full height bays or bows.

Bay windowsHaving multiple panels in them allows more light is allowed in to the room when compared to a standard “non-projecting” window.

Of the two designs a Bow window is likely to allow more light into the room than a bay window, as it is comprised of more glass panels.

One of the nicer features of a full height bay window is that it can incorporate a lovely seating area in the bay itself. With the main picture window being flanked by side windows it’s a light and airy place that offers a 180-degree view of the outside.

For bungalows, the eaves and soffit overhang can play the part of the weather proofing for the tops of the windows where they do not project too far out.

What do Bow & Bay Windows Cost?

It should come as no surprise that both the bow and bay windows can be more expensive than a standard flat plane window. They are big windows and require expert attention during installation. The other factor that is really going to influence the price, is the design of the window that you use for your bow or bay.

roof bay windowPrimarily you would be likely to use either Sash windows (double hung or single hung sashes) or casement windows in the bay or bow. Sash windows per window ,on a like for like basis (size wise), are more costly than casement windows.

Material used is also going to push the price up or down as, for example, a uPVC Sash Window will be a lot less expensive than a timber box sash one.

You also need to consider the top and the bottom of the window set. If you need to add a separate “roof” for the window, depending on what you want, it could be a significant factor.

For just some simple “lead flashing”  or a uPVC top section, then the cost will be minimal. But if you are going to need a fancy tiled cover or something more elaborate then the cost could jump a lot.

uPVC Bay Windows Prices

Bay Window Approximate size & panel numberMaterial Used General Price Guide
 8 feet  x  5 feet (2.5m x 1.5m) 3 panel Bay Window uPVC White£1,000 to £1,300
 10 feet x  5 feet (3.0m x 1.5m) 4 panel Bay WindowuPVC White£1,400 to £1,700
 13 feet x  5 feet (4.0m x 1.5m) 5 panel Bay WindowuPVC White£2.000 to £2,500

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

Bow Window Approximate size & Panel NumberMaterial Used General Price Guide
 11′ 6″ (3.5m ) 5 panel Bow Window uPVC White £1,500 to £1,800
 13′ 1″ (4.0m) 5 panel Bow Window uPVC White£1,800 to £2,000
 13′ 1″ (4.0m) 5 panel Bow Window uPVC Coloured£1,800 to £3,000


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Free quotesBe it bay or bow that you choose, both make a big style statement on the aesthetics of your home and both enhance the “kerb appeal” and maybe even the of your house.

But to choose between the two, you should contact an expert who can inspect your house and provide you a professional opinion on the subject so that the choice is made easy for you.



John Francis James
John has been around the building industry since he was a child. With a degree in civil engineering, John is a highly valued contributor to our website.