Whether you’re choosing replacement windows for your home or new windows for an extension, you’ll find one thing in common—a confusing number of choices. With many different window styles and a wide range of frame materials and opening options, plus varying costs, it’s important to do your homework before you buy.
While everyone’s needs will vary, the best windows should be easy to clean and maintain, let in plenty of light, suit the style of your home (such as sash windows for a period property), keep out draughts and insulate to reduce your energy bills, and be secure. They should also last for years to come and have a guarantee that covers the entire window (not just the glass).
We’ve reviewed the most common types and styles of windows in our guide below, including double-glazing and uPVC windows.
Styles of Windows
There are six main styles of windows:
- Casement windows
- Sash windows
- Bay windows
- Tilt and turn windows
- Fixed windows
- Roof windows
We’ll explain the features and benefits of each of these windows so you can decide which one is best for your home.
What Are Casement Windows?
One of the most popular types of window, a casement is a window that is attached to its frame by hinges. This means that they can open from the left or right side, or are hinged at the top or bottom. When they’re hinged at the top, they’re referred to as awning windows; when they’re hinged from the bottom, they are called hopper windows. You can also find them hinged in the centre to create a window that pivots to open or as a smaller top light combined with a fixed pane window.
As casements are versatile and effective at ventilating a room, they’re suitable for multiple uses. They are also reliably secure as casements can be made to lock at multiple points along the frame. A simple design and a wide choice of frame materials mean that casement windows are a good fit for most styles of home, including traditional properties as well as new builds, and they are easily combined with fixed pane windows.
Pros & Cons
Pros
- Affordable, especially if you need large windows
- Good for instant ventilation
- Can be angled to direct breezes into your home
- Have airtight seals that prevent heat escaping, which saves on energy bills
Cons
- Wide-opening windows may be unsuitable for those with small children and pets
- May not be suitable style-wise for some period properties
- Swinging clearance often required outside the window
Potential Costs
Depending on the size and material you choose, casement windows can start around £300–£500 each, with white uPVC being the most economical choice.
What Are Sash Windows?
If you’re shopping for a traditional-style window, look no further than sash windows. Sometimes referred to as vertical sliding sashes, windows move up and down on tracks to open and close. Typically, they have two window sections, one above the other—the top section slides down while the bottom slides up, although there are also horizontal sashes. Traditional sash windows operate using a pulley system of cords and weights; however, modern sashes have a rod and spring mechanism hidden within the frame. This takes up less space, allowing for a larger expanse of glass and more daylight into the room.
Thames Valley Window Company, https://www.tvwindows.com/ | Timber sash windows
Sash window frames can now be made from uPVC for a good balance between style and function. However, if you’re faithfully restoring a period property, timber sash windows can be a better option, but they do require more maintenance. Another option is tilt sash windows. These look like standard sashes but, in addition to sliding, one or both of the sashes tilt inwards so they can be cleaned easily.
Pros & Cons
Pros
- Vertical tracks won’t get clogged up with dirt like horizontal mechanisms can
- Modern opening mechanisms allow for slimmer frames
- Different period styles available including Georgian, Victorian, and Edwardian
Cons
- Timber frames require more maintenance than uPVC
- Mechanisms can have a short lifespan compared to other windows or may need to be repaired or replaced
- Replacement windows may need to be made in bespoke sizes, adding to the cost
Potential Costs
Depending on the size and material you choose, sash windows can start around £550–£625. While it may be cheaper to restore original sashes, new sash windows that are triple- or double-glazed will deliver savings on your energy bills.
What Are Bay Windows?
Less a type of window and more a style, bay windows project outwards from a building, making a room feel more spacious. Traditionally, they’re formed from three sections of glass—usually a picture window flanked by two side windows, which is sometimes referred to as a canted bay window. The windows can be sashes or casements combined with fixed panes or just fixed panes. This extra space is ideal for creating a window seat with a view, a cosy breakfast area, or even a desk for a light-filled workspace at home.
Crittall www.crittall-windows.co.uk | Bay window in steel
Another option is a bow window, which also projects out from a building, but usually less so than a bay window. These are made from four or five identical panes of glass fitted at an angle to create a curved bow shape. They provide the same panoramic views while introducing more daylight than a bay window. You may also come across oriel windows—this is a type of bay window that doesn’t reach the ground, meaning that it requires extra support from corbels, brackets, or cantilevers. It’s usually found on the upper floors of a property.
As bay, bow, and oriel windows are more complicated structures than, for example, a basic casement, it’s worth investing in good-quality sections, given that cheap options can warp, creak, and leak over time.
Pros & Cons
Pros
- Increases natural daylight—great for dark rooms
- Can add value to your home
- Creates a versatile space with a view
- Adds a period-style focal point
Cons
- Can be expensive to install, especially if the basic structure isn’t in place already
- Takes up space outside your home
- Best to use a specialist installer
- A new bay window replacing flat windows may require planning permission
Potential Costs
As they’re more complex to install and consist of multiple panes, bay windows can be expensive. Average prices start from £1,000–1,300 for a three-section bay in white uPVC, and £1,650–2,100 for a four- or five-section bow window.
What Are Tilt and Turn Windows?
Think of a tilt and turn window as a variation on a casement. It’s attached to its frame by dual hinges, but instead of opening outwards, tilt and turn windows open inwards, from either the side (turning) or by tilting inwards so they’re ventilated from the top while still being attached at the bottom. The window can’t be tilted and turned at the same time.
IQ Glass https://www.iqglassuk.com | Tilt and turn windows
Tilt and turn windows tend to suit more modern homes and are often found on upper storeys or apartments as they’re easy to clean from inside the property. They’re also a good choice for extensions, orangeries, and conservatories, providing a choice of a little or a lot of ventilation when required, and come in a range of finishes and materials, much like casement windows.
Pros & Cons
Pros
- Easy to clean and maintain from inside
- Tilted position provides safe ventilation if you have small children or pets
- Choice of fully ventilated position or less ventilation when tilted
Cons
- Opening inwards requires space in the room
- Not as cost-effective as casement windows
Potential Costs
Tilt and turn windows tend to be more expensive than casement windows because of their flexibility. Prices tend to start around £450–500 in white uPVC.
What Are Fixed Windows?
Fixed windows are precisely that—static panes of glass that don’t open. They’re often referred to as picture windows, installed to let light, rather than ventilation, into the room or to showcase the view outside. As well as rectangular glass, you can also find fixed windows as circular or shaped portals that help to let light in—great for dark rooms where an opening window would be impractical. Because there’s no opening mechanism, basic fixed pane windows are affordable, although the more intricate the design or detail, the higher the price.
IQ Glass https://www.iqglassuk.com
Pros & Cons
Pros
- Cost-effective
- Secure as there’s no opening mechanism
- Great way to frame a view with a large section of glazing
- Low maintenance
Cons
- Doesn’t provide any ventilation
Potential Costs
As they’re an affordable option, it’s no surprise that fixed pane windows start around £150–200 in uPVC.
What Are Roof Windows?
When windows in your walls don’t provide enough natural light or ventilation, it’s time to think about fitting windows overhead. Roof windows, also referred to as roof lanterns or rooflights, are fitted into a flat or pitched roof and are usually opening windows. They can sometimes be operated with a remote control, which is handy if they’re out of reach. They’re ideal for new spaces—such as extensions, orangeries and loft conversions. In loft spaces, they may also be installed to take advantage of a great view. They may also be called Velux windows; while a brand name, this has become more of a generic term.
Velux https://www.velux.co.uk/ | Roof windows
You can also find skylights, which tend to be fixed windows in the roof—their primary job is to bring daylight into dark spaces, rather than ventilation. These tend to be most suitable for brightening up previously extended or converted spaces, such as side returns, or large extensions where ventilation is provided elsewhere.
Pros & Cons
Pros
- Boosts daylight and ventilation in dark or new spaces
- Doesn’t take up wall space
- Ideal for loft conversions and extensions
Cons
- Expensive
- Can be tricky to keep clean
Potential Costs
Prices for a roof window tend to start around £900 to replace a window in an existing opening. However, the installation costs for creating a new opening and installing can be around £800–1,100 plus the cost of the window, which starts around £450–550.
Types of Window Materials
Window frames can be made from different types of materials. These are the common options:
- uPVC/PVCu double-glazed windows
- Wooden/timber windows
- Aluminium double-glazed windows
We’ll explain the features and benefits of each of these materials so you can decide which one is most suitable for your home.
uPVC Double-Glazed Windows
PVCu or uPVC, which stands for unplasticised Polyvinyl Chloride, is a lightweight and robust material that can withstand even harsh weather without the perils of rot, rust, or flaking that can occur with other materials. It’s also one of the most energy efficient available, especially when combined with double glazing. It doesn’t need painting, is low maintenance—only needing a wipe down from time to time to stay looking great–and is affordable. All of these characteristics make it the ideal material for window frames.
However, it can lack appeal. The most common and affordable colour, white, isn’t for everyone, plus the frames tend to be chunkier than aluminium, for example. And while cheap windows are available, it’s a good idea to invest in the best you can afford, as poor-quality uPVC can warp over time.
On the plus side, smooth white frames are no longer the only choice. There’s an increasing number of styles and colours available beyond white uPVC, including wood grain textures, browns and greys, and moulded effects that suit traditional homes.
Pros & Cons
Pros
- Multiple style and colour options
- Affordable
- Low maintenance
- Long lasting
Cons
- Poor-quality uPVC can warp
- Quality varies with price
- May affect the value of a period home
- Chunky frames can obscure a view
Potential Costs
While affordable, you’ll still need a good-sized budget to replace all the windows in your home. The average cost for 12 uPVC windows on a three-bedroom house is around £6,000, with an increase of around 30% if you choose triple rather than double glazing.
Wooden/Timber Windows
Timber frames are often the priciest option but can add real value to your home, especially if it’s a period property. Classic and elegant, they’re perfect for personalising your exterior as they can be stained or painted—as well as repainted or refinished when you fancy a change or a refresh. Plus, as timber is a natural insulator, it retains heat and helps to keep out the cold in the winter months, making it energy efficient.
Timber is available as softwood (such as pine, yew, cedar, and fir) or hardwood (such as oak, beech, and maple). Faster-growing softwood is more affordable but needs maintenance and repainting, while hardwood will be more expensive (up to four times the cost of softwood) but will be more stable and durable in the long term. Modern frames tend to be solidly engineered to prevent warping and are usually treated to prevent rot. Cared for properly, timber windows will last for decades.
Pros & Cons
Pros
- Can be personalised with stains and paint
- Ideal for period properties
- Tactile and adds texture
- Can be repaired if damaged
Cons
- Higher maintenance than uPVC or aluminium
- Can rot if not treated
- Expensive
Potential Costs
Prices for timber vary depending on the wood chosen, the style and also the quantity you buy, but, roughly, prices for a single casement are around £925, rising to around £1,490 for a sash.
Aluminium Double-Glazed Windows
Strong, low maintenance, and weatherproof, aluminium is more expensive than uPVC but brings a lot to the table. Its strength means the frames can be slimmer, even while accommodating heavy triple or double glazing, making for fewer bars and larger expanses of glass, which equals more daylight. Aluminium can also be used for structural glazing. This makes it ideal for contemporary homes, although period-style aluminium windows are becoming more popular. A range of power-coated finishes means there’s more colour choice than dark grey, too.
Where aluminium also differs from uPVC is its energy efficiency. Aluminium as a metal is a conductor, so heat can be lost through the frames. This means that aluminium windows need to have a thermal barrier (sometimes referred to as thermally broken or a thermal break), which refers to insulation between the inside and outside frame, to improve the energy efficiency. And if you’re looking for an eco-friendly choice, you’ve found it. Aluminium is completely recyclable at the end of its lifetime.
Pros & Cons
Pros
- Won’t rot, flake, or rust
- Low maintenance
- Strong and stable
- Long lasting
Cons
- More expensive than uPVC
- Colour choice can be limited
Potential Costs
Price-wise, aluminium double-glazed windows sit somewhere between uPVC and timber, starting around £500 each.
Verdict and Recommendations
Double glazing is a good choice for many reasons—it’ll help lower your energy bills, keep your home warmer in the colder months, and reduce noise from outside. However, the materials and window style you choose will depend largely on your circumstances. Our top recommendation for most homeowners would be good-quality uPVC double-glazed windows, as they deliver value for money with virtually no maintenance.
If budget allows and it delivers the look you want, aluminium windows are a great alternative and may be worth the investment for their increased daylight and eco-friendly credentials.
Remember to take your time when considering the type and style of windows as once they’re installed, you’ll potentially be living with them for decades. Start by requesting quotes from several companies to make the best choice for your budget and requirements.