A bay window is a set of three or more windows that project outwards from the main wall of a house, creating extra space and allowing more light into a room. They can be full-height or sit above a dwarf wall, and are often seen in Victorian, Edwardian, and modern homes across the UK.
This guide explores what makes bay windows special, why homeowners choose them, the different types available, costs, planning considerations, and a comparison with other window styles.
How Do Bay Windows Work?
Bay windows have three main parts:
- Central window: The fixed or openable middle pane.
- Flanking windows: Two angled windows on either side.
- Supporting structure: These can project from the wall with frames or sit on a small base.
This design increases natural light, creates a cosy alcove inside, and adds kerb appeal. Bay windows also improve room airflow when the outer panes are open.
Why Choose a Bay Window?
Here are the main benefits of installing a bay window:
- Extra space: Creates a cosy alcove inside—a reading nook, window seat, or display shelf.
- Increased light: Multiple panes allow more daylight from different angles.
- Aesthetic appeal: Adds architectural interest to both interior and exterior.
- Versatility: Works well in lounges, dining areas, bedrooms, or studies.
- Improved property value: Many buyers appreciate the charm and space bay windows provide.
Types of Bay Windows
Several styles of bay windows cater to different home types and tastes:
1. Box Bay Window
A square or rectangular projection with three windows, often seen on modern homes. Offers ample internal space.
2. Canted Bay Window
Has angled side windows, typically at 45 degrees from the central panel. Common in Victorian and Edwardian houses.
3. Oriel Bay Window
A smaller first-floor bay window supported by brackets or corbels. Often found in older buildings as a decorative feature.
4. Curved or Bow Window
Made up of four or more windows forming a sweeping curve. These windows create a dramatic visual and spacious feel inside.
Materials Used for Bay Windows
Bay windows come in a range of materials to suit different needs:
| Material | Appearance & Maintenance | Suitability |
|---|---|---|
| uPVC | Low-maintenance, durable, energy-efficient | Commonly used in modern homes |
| Timber | Natural and traditional, but high-maintenance | Best for period properties |
| Composite | Timber core with outer layers for weather protection | Ideal for long lifespan with low upkeep |
| Aluminium | Very strong frames, slim sightlines, modern look | Fits contemporary homes |
Energy Efficiency & Insulation
Bay windows can be efficient if done right:
- Modern options include double or triple glazing with low-E coatings.
- Sealed frames reduce draughts.
- Some designs allow for internal insulation on the supporting wall beneath.
Make sure your bay window frames are A-rated with BFRC-rated glazing for maximum efficiency.
Planning Permission & Building Regulations
Most bay windows fall under “permitted development,” meaning you won’t need planning permission if:
- The extension is past the front wall
- It doesn’t exceed one storey
- Materials match the main house
However, if you live in a conservation area or have a listed building, always check with your local council. If planning permission is required, your installer may help with the paperwork.
All new windows must meet UK building regulations for safety, insulation, and ventilation. A FENSA-registered installer will ensure compliance and provide certification.
Cost of Bay Windows
The price varies depending on size, material, glazing, and installation complexity:
- uPVC canted bay: £1,200 – £2,500
- Timber box bay: £2,000 – £3,500
- Bow or large curved bay: £3,000 – £6,000+
These prices usually include fabrication, fitting, VAT, waste removal, and finishing inside/outside. Always ask for a full quote from a certified installer.
Maintenance Tips for Bay Windows
To ensure your bay window lasts:
- Clean panes and frames regularly to prevent dirt buildup
- Check the sealing and watersill drainage in rainy seasons
- For timber frames, repaint or re-stain every 5–8 years
- For uPVC or composite, wipe clean and inspect seals annually
Proper care lengthens lifespan and keeps your window looking its best.
Choosing the Right Style for Your Home
Here’s how to pick the best bay window style:
- Modern homes: Box bay with full-height glazing
- Victorian/Edwardian homes: Canted bay with timber or woodgrain frames
- Dining rooms or studies: Bow windows for curved seating areas
- Upper floors or decorative purposes: Oriel windows
Materials matter too: uPVC offers easy care, timber adds authenticity, composite mixes both, and aluminium brings a sleek, contemporary feel.
Installation Process
A typical bay window installation includes:
- Online or on-site survey to measure and inspect
- Manufacturing the window units (usually takes 4–8 weeks)
- Removal of old structure if needed
- Fitting and securing the frame
- Sealing, plastering, and internal finishing
- Ensuring energy and safety standards are met
- Issuing a FENSA certificate
Installers should manage logistics, including scaffolding if necessary. After completion, check that your room is clean and all fixtures are tested.
Ideal Uses for Bay Windows
Bay windows enhance many spaces:
- Living rooms: Create a bright reading corner
- Dining rooms: Offer a light, outlook-rich eating area
- Kitchens: Provide space for herbs or stools
- Bedrooms: Add a cosy nook or window seat
- Studies: Bring in more daylight and workspace
They suit any room where light, space or aesthetics matter.
Comparison Table: Window Styles
Here’s a helpful overview of popular window types:
| Window Type | How It Opens | Best For | Maintenance | Style |
|---|---|---|---|---|
| Bay Window | Fixed or open side panes | Light, space, architectural interest | Low-medium (uPVC/timber) | Decorative |
| Casement Window | Hinged at the side | Ventilation, modern properties | Very low (uPVC) | Contemporary |
| Flush Fit Window | Sits flush with frame | Minimalist or modern designs | Very low (uPVC) | Sleek/Modern |
| Sash Window | Vertical sliders | Period homes, traditional look | Low (uPVC), Medium (Timber) | Classic |
