What are Bow Windows and are they Better Than Bay Windows?

By thewriteDuffy •  Updated: 06/07/24 •  7 min read

Though bow windows undoubtedly suit the Edwardian and Victorian style of architecture, bow windows can also make a stunning addition to a modern home. 

Bow windows are a particularly superb addition to your property if you have a beautiful garden or landscape to admire, or a striking urban outlook as they give you a panoramic view.

Why Do They Call It a Bow Window?

Also known as compass windows, bow windows are reminiscent of archery bows and get their name from their shape. Rather than the window panes themselves being curved,  bow windows get their rounded shape by setting flat window panes at an angle to one another to create a gentle sweep of a curve.

To achieve this curve from flat window panels, individual windows (usually of the same size) are placed at 130 or 150° degree angles. Four or more individual panels are typically needed to get the shape right.

The nature of a bow window makes it trickier to install than other styles, especially in terms of the curved framing with wood. 

We’ll get into the building concerns involved in bow windows, but first let’s differentiate them from their siblings, bay windows.

Bow Windows vs. Bay Windows: What’s the Difference?

Bow and bay windows differ both in shape and in the number of window panes included with

Bow windows form a curve thanks to the angles between the four or more contributing panes while bay windows are angular, box-like protrusions made of three panes. Importantly, bay windows increase your floor space but bow windows generally don’t.

You can click here for a full article all about bay windows, but to help you decide which of the two you’d be more interested in, here’s a quick table showing the key differences.

Bow WindowsBay Windows
Most often four or more windowpanes of the same size set at internal angles of 90 degree, 130 degree, or 150 degree angles.Most often just three window panes of different sizes set at inside angles of 90 degrees or 135 degrees, though triangular bays formed by two windows set at 120 degrees are often found – called Oriel bay windows.
Creates a round shape. Creates a box shape.
Don’t offer floor space but can offer a sizable window sill. Often offer “usable” floor space.
Allow for more light than a bay window, and better views. Offer less light than bow windows, but still provide a ton of light and good views.
Don’t usually require foundation work (see below). May require a foundation or footing depending on your local building codes.
More expensive than a bay window to purchase the window, but installation may be cheaper.Less expensive to purchase the window itself than a bow window, but installation may be more costly.

Are Bow Windows Expensive?

Because bow windows are composed of four or more individual window panes, they do tend to be more expensive than other styles.  Not only are the material parts of a bow window more expensive, the labor involved in fitting this style needs to be taken into account too, especially if you’re replacing a different type of window with a bow.

On average, a bow window costs $3,600. On the lower end of the scale, you can find a bow for under $2000, while top quality offerings sit at around $6000. You’ll need to factor in the cost of fitting too, with installation costs for replacing a bow likely to be between $3000 and $4000.  If it’s a first time installation, this figure will be higher due to the time required to build the framing.

Installing bow windows is a skill, though an experienced diy enthusiast can certainly take on the task.  Proper installation is key though, to ensure the windows maintain their energy efficiency and to prevent leaks and airflow between individual panes. The draw of a bow window is that enchanting curved shape, and it takes carpentry skill to achieve a high quality finish here.

Do You Need Planning Permission for A Bow Window?

No.  So long as your bow is a traditional style, protruding out from above ground level or from an upper floor you do not need planning permission because their installation will not increase floor space within your interior.  Not be confused with bays, bow windows are not classed as an extension to your home.

Homeowners who fall in love with a bay window often have their hearts broken when they find out that they’ll need planning permission if they’re adding them to the front of their property.  Bow windows offer a paperwork-free alternative to bays, and a highly attractive one at that, letting in more light and opening up the view from your chosen room.

If you’re planning on a non-traditional bow window, creating a protrusion from sill-height down, then you may well need to seek planning permission due to the increased floor space.  This is more likely to be necessary if you’re adding it to the front of your property, rather than to the side or rear.  Whatever style of bow you’re planning, if your home has never featured the style, check with your local building authority because you’re ultimately going to be changing the appearance of your property.

Bow Window - exterior

Can You Sit on A Bow Window?

A deeper bow window may allow you to create a narrow seating area, but it is the bay style of window that is better suited to creating a window seat.   

The angles between the individual panes of bow windows don’t add great depth to the overall structure, unlike the angles featured in a three-paned bay window.  If you’re looking for a window seat that you can enjoy turning into a cozy reading nook or a people-watching spot, a bay is a better option for you.  If you’re keen to make at least a spot to perch within your bow window, you can discuss angles with your builder, to try and maximize your depth.

Though bows aren’t ideal for a seating area, their length makes them a great spot for displaying your much-loved items or floral displays.  Or left empty, the slender and elongated bow window sill can add the illusion of breadth to a room – perfect for smaller spaces or larger rooms that you really want to showcase in terms of their expanse.


Bow windows are a timelessly elegant style, adding interest and charm to the exterior of a property.  They’re a winner when it comes to letting in natural light and showing off your view too. 

The classical bowed shape has great potential within both period and modern homes.  The curvature provides a striking focal point in a room and if you’ve got archways in your home, bow windows help to echo this curved architecture.

Bow windows also have great curb appeal especially upper floor bow windows, which have a turret-like appearance. So in short, if you’ve got your heart set on the fairytale look of a bow window, they’re well worth the price tag. 

But, if you’re still not quite sold on a bow window for your property aesthetic you can click here to see our list of the 13 most popular window styles for your home.


At home, April is a mom, wife, and DIY darling. Among other home projects, she helped her husband Dan renovate their 1986 bungalow and is currently designing and decorating the 2023 custom home they are building themselves. Professionally, April is a writer, author, and online marketer with 15 years of experience writing for newspapers and magazines, building online authority websites, and publishing books.