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Bay Windows: The Complete Guide

a bay window with double glazing

Bay windows are one of the most popular styles in UK homes

You can expect to pay between £2,000 and £8,000

They can make a room look bigger


Bay windows look magnificent, which is probably why they're so popular across the UK.

We've gathered all the information you'll need to know before deciding whether or not to make the switch to this lovely window style.

If you've already made your mind up, just fill in this quick form to get free quotes from our trusted suppliers.



What's on this page?

Head straight to a specific section by clicking on the links below


What are bay windows?

Bay windows are much more than just pieces of glass in frames. They’re the ones that arc out of buildings – just like a bay – to create more space, and let even more light in.

It’s no wonder they’re so popular in UK homes. Sound familiar? You may have square edges, or a polygonal shape, a boxed shape or a nice curve.

Other than their unique form, these windows have much in common with alternative window designs. The best known frame materials for bay windows are aluminium, wood or uPVC.

You can have regular or double glazed bay windows. The sturdy frame helps the windows last well, but because of the additional windows needed to fill the space, they can cost more than others.

If you want to make sure you get the best deal on your bay window, fill in this form and get quotes from trusted specialists.


Benefits of bay windows

Wondering why bay windows are so popular? A big reason is cosmetic. The arched shape opens up the view you get to enjoy from inside, with more angles available to look out from.

Of course, many people also appreciate the extra space this type of window creates. You may like to use the ledge to showcase your decor, or even as your favourite reading spot.

Are there any disadvantages? Of course, it can be a pain to install a bay window from scratch, not to mention the extra time involved.

And as you would expect, this slightly more complex design tends to cost more than other options. We recommend finding a qualified installer you can trust, as trying to cut costs here can let you down in the long run.

This guide tells you all you need to know about double glazed bay windows today. Find out which type yours are, and how much new ones will cost you. Plus, you can discover which companies near you can help you get one fitted.


  • They look great
  • They create more space in your room

X Cons:

  • More expensive than other designs


Types of bay windows

Bay windows come in a wide range of varieties, and you’ll likely find one to suit your personal budgets and preferences. Most often, bay windows are made from uPVC, but wooden and aluminium frames are also available in the UK.

Once you’ve picked the frame material you’d like, the next step is to ask yourself whether you’re looking for double or triple glazing.

As you’d expect, triple glazing costs a tad more, but may be worthwhile if you’re bent on cutting your energy bills. We explain more below.


Box bay windows

You guessed it: boxed bay windows are shaped just like a box. They are rectangular, with three flat sides, just like a bay.

You’ll mostly find this style across Europe, and may also hear them referred to as canted windows.


Free standing bay windows

Free standing bay windows look like three-dimensional casement windows. In this style, the bay has the same dimensions as the window..


Integral bay windows

You have integral bay windows if the structure forms an integral part of the house walls, for instance if they reach up to the ceiling.

In some cases, integral bay windows can even go all the way up to the roof, as in many period homes.


Bay vs bow windows

Bow windows – or bowing bay windows – are a curve-based model. Traditionally, this style uses flat glass panes with multiple frame segments to create a curved bay.

A subcategory of bowing bay windows is circle bay windows. They use curved glass panes to create a semi-circle shape.

You can tell these apart from bow windows, as the curve is much more pronounced.


Best bay window materials

uPVC is the most popular material for all window types in the UK. That’s because it’s the cheapest, and its durability helps it stand the test of time.

Why pay more for wooden sash windows? It’s a personal choice, but for some people it’s worth splashing out on wooden sash windows, as the wood finish can add value to your home.

Did You Know?

uPVC double glazed bay windows tend to cost between £300 and £950 per window.

Another option is to go for aluminium windows. They cost a bit more than uPVC, but last well, and many people like the look.

Whichever material you end up opting for, remember that changing the window frame in a noticeable way may require planning permission, especially if you’re wanting to replace wood with plastic, so don’t be caught out.


Double glazed bay windows

After double glazed sash windows, double glazed bay windows are a popular choice of new window in UK homes.

So, are they worth it? Double glazed windows enjoy two panes of glass. That way, they are able to insulate you from outside nuisances, such as noise and pollution.

At the same time, you can look forward to keeping in what you don’t want to lose, such as your heating that you pay so much for each month. Double glazing can help reduce these costs.

Double glazed windows wouldn’t be so common if they didn’t make a difference, but don’t expect 100% results – you’ll be able to significantly reduce but probably not completely remove your bugbear.

So, how does double glazing work? Double glazed windows have two panes of glass, instead of one. In between them, there’s a layer of gas (usually argon), which insulates them. That usually means a warmer home (lower heating bills, check), as well as a safer one, since it’s harder to break through two panes of glass than one, and people are much less willing to try it.


Triple glazed bay windows

Of course, triple glazed bay windows are also an option. As you probably already know, triple glazing uses an extra layer of glass, giving you three panes instead of two.

Why get triple glazing? Triple glazing has many of the same benefits as double glazing, just to a larger extent.

You can expect dialed up sound and heating protection. But of course, this extra glass costs more, so you may like to seek quotes, and decide whether this step is right for you.

Read our guide on triple glazed windows to find out if they're what you’re looking for.


How much does a bay window cost?

So, how much do bay windows cost? Of course, with so many style options and dimensions, the price for your individual home will vary.

But as a rule of thumb, you can expect to pay somewhere in the region of £2,000 to £8,000 to have a new bay window installed.

The cost of double glazing bay window starts from around £300, and companies charge up to £900 per pane of glass, depending on the size and finish you go for. Hopefully, that can help you calculate what price you may face.

The cheapest type of bay windows is using uPVC material. uPVC double glazed bay windows tend to cost between £300 and £950 per window.

But bowing or circle bay windows can cost more, due to the difficulty in shaping the glass to fit.

Window Size
2500 x 1500 (3 panel)
£1,000 to £1,300
2500 x 1500 (3 panel)
£1,300 to £1,500
3000 x 1500 (4 panel)
£1,400 to £1,700
3000 x 1500 (4 panel)
£1,700 to £2,000
4000 x 1500 (5 panel)
£2000 to £2,500
4000 x 1500 (5 panel)
£2,500 – £2,750
3500 x 3500 (5 panel Bow)
£1,500 to £1,800
3500 x 4000 (5 panel Bow)
£1,800 to £2,000
4000 x 4000 (5 panel Bow)
£1,800 to £3,000

*Prices exclude installation costs.

*Based on a survey we conducted in May 2018 of 42 UK homeowners who've had double glazed bay windows installed in the last two years.

If you’re worried about the price of your new double glazed bay windows, it’s good to know most companies will offer you the option of buying them on finance. That lets you spread the cost over several months and only pay potential interest, if any.

Keen to save on bay windows? If you’re on a budget, consider uPVC frames, rather than timber and aluminium.

Just take care when buying on finance that you don’t end up paying hundreds. And make sure you won’t fall behind on payments, and face any unfortunate penalties.

You may even be entitled to Government support in double glazing your windows. To find out, you can read our guide to double glazing grants here.


Installing and repairing bay windows

The largest double glazing installers in the UK are Anglian, Everest, Safestyle and Zenith, and all can fit bay windows.

Why choose a big company? Many people like to go to these companies because they trust them more than local suppliers.

Of course there is no guarantee wherever you go, but a nationwide brand is likely to offer quality windows, and reliable installations. Plus, there’s help at hand if anything goes wrong.

This is the range of new windows or double glazing repairs on offer with these suppliers:

Let’s have a look at their range of uPVC double glazed sash windows:

Energy Rating
A++ to A
10 years
10 years
10 years
10 years

Fitting costs will vary, so it’s worth seeking at least three quotes from different suppliers, and picking the one you like best.

So, should I look locally or nationwide? That’ll be your decision. You often have more support if anything goes wrong with a larger company. But a long-standing independent window installer with good ratings may also be trustworthy.

To help you make the right decision, try to find a company that’s accredited by one of the Government’s Competent Persons Schemes (CPS), FENSA or CERTASS.

The CPS scheme is designed to tell you whether your window fitters are fully qualified, reliable, and compliant with all relevant Government building regulations.

But the main benefit is the protection you get. On the off chance anything is not as you’d expect, you’ll be able to rely on a full complaints procedure, with an ombudsman included.

Every company featured on Eco Experts is accredited by the CPS. Or, you can find any more on the FENSA register or the CERTASS register.

To get quotes from these well-respected companies, just complete this form.

Jonathan Whiting
Jonathan Whiting

An eco hero with a head for numbers, Jon’s data visualisation skills are legendary. Whether it’s determining what countries will survive climate change or the animals most at risk from it, he has the planet’s best interests at heart.

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