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uPVC Window Guide

Our comprehensive uPVC windows guide is here to help explain all about uPVC windows and their benefits to you. It will help guide you towards making an informed decision about uPVC windows and will explain all the advantages of choosing uPVC as a window frame material and the various glazing options available. We’ll also look at window security options,  explain energy efficiency and look at the differences between the various WER A ratings!

Why Choose uPVC Windows?

Selecting the right material for your new windows is key. uPVC windows are an excellent choice, offering several benefits that cater to durability, energy efficiency, maintenance, security, and style.

Durability and Longevity

uPVC is highly durable, and resistant to rotting, warping, or corroding, ensuring your windows last for years.

Energy Efficiency

With superb insulation properties, uPVC windows keep your home warm in winter and cool in summer, helping to reduce energy costs.

Low Maintenance

Requiring just a simple clean with soapy water, uPVC windows are low maintenance, freeing up your time for more enjoyable activities.

Enhanced Security

uPVC windows come with strong locking systems and robust frames, offering peace of mind with enhanced security.

Customisation Options

Available in a variety of colours, finishes, and styles, uPVC windows can be customised to fit any type of home.

What Are The Different Types of uPVC Windows?

Choosing the right type of uPVC window can significantly enhance the appearance and functionality of your home. Let’s explore the different styles of uPVC windows available and look at what types of homes each suits best.

Casement Windows

Casement windows are one of the most popular and versatile uPVC window styles, characterized by their hinged design that allows them to open outwards with sashes that can be either side hung or top hung.. Their clean, simple lines make them suitable for a wide range of styles of home, whether traditional or modern. They offer excellent ventilation, easy operation, and a clear view of the outdoors, making them a popular choice in many homes. They can be configured to comply with fire safety requirements for compliance with building regulations and maximise light and air circulation.

Ideal for: Modern or new builds and traditional homes alike, great in living rooms and kitchens where maximising light and air circulation is important.

Sliding Sash Windows

Sliding sash windows (sometimes referred to as vertical sliders) are distinguished by their vertical sliding mechanism, which provides a classic, elegant look reminiscent of period properties. These windows are ideal for homeowners looking to retain or enhance the historical charm of their property without sacrificing the benefits of modern uPVC technology, such as improved energy efficiency and security.

Ideal for: Victorian, Edwardian, and other heritage homes where maintaining or enhancing the property's historical value is crucial. They're also often well-suited for homes in conservation areas.

Tilt and Turn Windows

Tilt and turn windows offer a unique blend of functionality and security, with a dual opening hinge mechanism allowing them to either 1. tilt inwards (hinged at the bottom) to be left in this tilted position for ventilation or 2. by simply turning the window handle 90 degrees the opening sash can then open fully into the room.

This open-in position makes for extremely easy cleaning from the inside of your property as the window sash will be right in front of you inside the room it is situated when you open it fully into this position.  This dual functionality makes tilt and turn windows particularly suited to high-rise apartments or homes where window access for cleaning is challenging. They can also serve well as fire escape windows because the side opening hinges pivot right into the corner where the hinges are mounted so they open nice and wide. Their contemporary design also fits well with modern architectural styles. Please note if you have blinds or curtains because of the nature of these windows tilting-in or opening-in, they can sometimes clash with blinds, shutters or curtains etc and this may need to be considered. Also bear in mind that tilt and turn windows only open in, they cannot open outwards at all.

Ideal for: Modern apartments and homes with limited external space due to the open-in style of operation. They can be beneficial for families with young children, thanks to the safety aspect of the tilt function for ventilation.

Bow Windows

Bow windows protrude from the exterior wall, creating a bay in the room that offers extra space and allows plenty of natural light to enter from multiple directions. They can dramatically enhance the character and space perception of a room. uPVC bow windows combine the traditional aesthetic appeal with the benefits of modern window technology.

Bay windows

Similar to a bow window but where the wall beneath the window follows the shape of the window facets which project out.

Victorian and Edwardian homes often have bay windows and they give a great extra dimension and add light to their rooms, such as living rooms or master bedrooms. They're can also be fantastic for creating window seats or cozy reading nooks.

What Are Your Glazing Options?

When selecting uPVC windows, the type of glazing you choose plays a crucial role in enhancing your home's energy efficiency, security, and comfort. There are three main types of glazing to consider for your windows.


Our Double-glazed uPVC windows are constructed with two panes of performance glass which are separated with a warm edge spacer bar around the perimeter of the two panes, whilst the cavity between the panes is insulated by a layer of inert gas, which is hermetically sealed inside. We refer to this as a double-glazed sealed unit and this unit which itself is completely air tight, is then fitted into the window frame itself which can achieve an A+ rating or beyond, depending on your budget and requirements. 

This design provides a vast improvement in thermal insulation compared to single-glazed windows, significantly reducing heat loss through windows. As a result, you can enjoy a warmer, more energy-efficient home with lower heating bills during the winter months. In addition to thermal benefits, double-glazing also offers enhanced noise reduction, making it an excellent choice for homes in busy areas where external noise can be a concern.


Taking the concept of double-glazing further, triple-glazed windows incorporate an additional pane of glass, creating two insulating layers. This setup offers superb energy efficiency, keeping your home warm whilst reducing energy bills.. The extra pane can also increase the window's strength, enhancing security against break-ins. Additionally, triple-glazing offers superior noise isolation, making it the premium choice for homes in extremely noisy environments or very cold climates where maximising energy efficiency and warmth is paramount.

Double-glazing with Acoustic Glass

Acoustic glass is a specialised type of glass engineered to reduce noise transmission and offers a range of benefits when used in double-glazing systems. Its unique construction incorporates a laminated layer within the glass pane, which is made of polyvinyl butyral (PVB) and this performance layer helps to dampen sound waves.

Acoustic glass absorbs and disperses sound energy, resulting in a quieter indoor environment. The advantages of acoustic glass over triple glazing lie in its superior noise reduction capabilities without the need for an additional pane. This means that acoustic glass double-glazing can provide comparable or even better sound insulation than triple-glazing, while maintaining a thinner and lighter profile. 

Acoustic glass also offers other benefits such as enhanced thermal insulation, UV protection, and better security making it a versatile choice for both residential and commercial properties where noise reduction is a priority.

Window Security

Modern uPVC windows offer a range of security features designed to protect your home from unwanted intrusions as well as keeping children and pets safe. 

Multi-Point Locking Systems

Multi-point locking systems are at the forefront of window security technology. Unlike traditional locks that secure the window at one point, multi-point locking systems secure the window at several points along the frame.. This distributed locking mechanism significantly enhances the window's resistance to forced entry, making it extremely difficult for intruders to pry the window open. When selecting uPVC windows, opting for those equipped with multi-point locking systems is advisable for the highest level of security.

Lockable Handles

Lockable handles add an additional layer of security to your uPVC windows. These handles come with a built-in locking mechanism that can be engaged with a key, preventing the window from being opened from the outside. Lockable handles are particularly useful for ground-floor windows or those accessible from flat roofs, where intruders might attempt to gain entry. They also offer a safety feature for homes with young children, preventing them from opening windows unsupervised.

Opening Restrictors

Opening restrictors limit how far a window can open, offering both security and safety benefits. They prevent windows from being fully opened from the inside, making it difficult for intruders to enter through the window. At the same time, they allow for ventilation without the risk of accidents, especially in homes with young children or pets. Opening restrictors are an excellent option for adding security while maintaining the functionality of your windows.

Energy Efficiency

When evaluating the energy efficiency of uPVC windows, two key metrics offer valuable insights: Window Energy Ratings (WER) and U-values. Let’s look at how these ratings work and their significance in enhancing your home's energy performance.

What is the Window Energy Rating (WER)?

The Window Energy Rating (WER) system provides a straightforward method to assess a window's energy performance. Rated from A++ (most efficient) to E (least efficient), WER considers not just heat loss through U-values but also gains through solar gain and air leakage. This comprehensive approach ensures you understand how well a window will perform in all aspects of energy efficiency. uPVC windows, known for their excellent insulation properties, can achieve high WERs, making them an ideal choice for those looking to improve their home's energy performance.

What are U-values?

U-values measure the rate of heat transfer through a window, indicating how well the window insulates. The lower the U-value, the better the window is at keeping heat inside during the winter and outside during the summer. In the context of uPVC windows, these values are crucial for determining how much energy (and, consequently, money) you can save on heating and cooling your home. uPVC windows, especially when double or triple-glazed, typically feature low U-values due to their superior design and materials, which enhance their insulating capabilities.

Double-Glazed uPVC Windows

Generally, these windows have U-values between approximately 1.2 to 1.8 W/(m²K), offering a balance between cost and insulation performance suitable for most homes.

Triple-Glazed uPVC Windows

These can reach U-values as low as 0.8 W/(m²K), providing even better insulation but at a higher upfront cost.

uPVC Windows Costs and Return on Investment (ROI)

Investing in uPVC windows is a significant decision for any homeowner and it’s important to balance the initial costs against the long-term benefits. 

How much do uPVC Windows cost?

The price of uPVC windows varies based on size, design, glazing options, and additional security features. On average, a standard uPVC window costs from a few hundred to over a thousand pounds per unit, with more sophisticated glazing and security features adding to the price. 

Also, consider the durability and longevity of new windows. uPVC windows can last up to 30 years or more with minimal maintenance, providing significant savings over time compared to wooden or aluminium alternatives.

Are uPVC windows a good investment?

The return on investment (ROI) for uPVC windows comes in two main forms: energy savings and increased property value.

Energy Savings

Upgrading to energy-efficient uPVC windows can significantly reduce heat loss, leading to lower heating bills. Over time, these savings can offset the initial cost of the windows. The exact savings depend on various factors, including the size of your home and the efficiency of the windows replaced, but reductions in energy bills can be substantial.

Property Value Increase

Besides energy savings, new uPVC windows can enhance the curb appeal and overall value of your home. Buyers often value the improved insulation, security, and low maintenance offered by uPVC windows, which can make your property more attractive should you ever decide to sell your home in the future.

Frequently Asked Questions (FAQ) About uPVC Windows

Q: Why should I choose uPVC windows over other materials?

A: uPVC windows offer superior energy efficiency, low maintenance, great durability, and cost-effectiveness compared to wooden or aluminium alternatives. They're also available in various styles and colours to suit any home.

Q: Can uPVC windows reduce my energy bills?

A: Yes, the excellent insulation properties of uPVC windows can significantly reduce heat loss, helping to lower heating bills by keeping your home warmer in the winter and cooler in the summer.

Q: Are uPVC windows environmentally friendly?

A: uPVC windows are a more environmentally friendly option as they have a long lifespan, are recyclable, and contribute to reducing energy consumption in homes.

Q: How long do uPVC windows last?

A: With proper care and maintenance, uPVC windows can last 30 years or more, making them a long-lasting addition to your home.

Q: Can I customize the appearance of my uPVC windows?

A: Absolutely. uPVC windows come in a variety of colours and finishes, including woodgrain effects, and can be designed to fit various window styles, ensuring they complement your home's aesthetic.

Q: Do uPVC windows provide good security?

A: Yes, modern uPVC windows are equipped with advanced locking mechanisms, including multi-point locks and lockable handles, enhancing your home's security.

Q: Are uPVC windows easy to maintain?

A: uPVC windows require minimal maintenance. They do not need painting or sealing and can be kept clean with just soap and water.

Q: Can I install uPVC windows in a conservation area or listed building?

A: Restrictions can apply in conservation areas or listed buildings. However, specific uPVC window designs that mimic traditional styles may be approved. Always check with your local planning authority first.

Q: What glazing options are available with uPVC windows?

A: uPVC windows can be fitted with double-glazing, triple-glazing, or acoustic double-glazing, depending on your needs for energy efficiency, sound insulation, and security.

Q: How do I know if a uPVC window is energy-efficient?

A: Look for the Window Energy Rating (WER) and U-values. Higher WER ratings and lower U-values indicate better insulation and energy efficiency. 

Q: What is the process for replacing my old windows with uPVC windows?

A: This will typically involve a consultation to discuss your needs followed by a home survey to take precise measurements should you decide to place an order with ZEN.. An installation date which is agreeable to you can then be booked and this is then followed by professional installation of your new glazing items by ZEN installers.

Your old windows are removed, and your lovely new uPVC windows are professionally installed by ZEN installers in their place; we will take care to protect your property during installation, using protective flooring and furniture coverings. We aim to install your windows and leave each room as though we had never been there, with your new glazing being the only clue that we ever were. Once removed we will dispose of your old windows and doors etc and all waste materials are recycled wherever possible. 

Q: What should I consider when choosing uPVC windows for my home?

A: Consider the window's energy efficiency, security features, style and design, colour and finish options, maintenance requirements, and overall cost to ensure they meet your specific needs and preferences.

Glossary of Terms

uPVC (Unplasticized Polyvinyl Chloride): A type of premium plastic commonly used in the construction of window frames due to its durability, energy efficiency, and low maintenance requirements.

Energy Efficiency: The ability of a window to retain heat and reduce the amount of energy required to heat or cool a home.

Window Energy Rating (WER): A rating system that measures the energy efficiency of windows from A++ (most efficient) to E (least efficient), considering factors like heat loss, solar gain, and air leakage.

U-values: A measure of how well a window can insulate, indicating the amount of heat that passes through the window. Lower U-values signify better insulation.

Double-Glazing: A window that has two panes of glass with a space between them, typically filled with air or inert gas, to reduce heat loss and noise.

Triple-Glazing: Similar to double-glazing but with an additional pane of glass, offering improved energy efficiency, noise reduction, and security.

Multi-Point Locking System: A locking system that secures the window at multiple points along the frame, enhancing security.

Lockable Handles: Handles with built-in locks that provide additional security by preventing the window from being opened from the outside.

Opening Restrictors: Devices that limit how far a window can open, enhancing safety and security.

Glazing Options: The different types of glass or treatments available for windows, affecting energy efficiency, noise reduction, and security.

Casement Windows: Windows that are hinged at the side and open outward or inward, offering good ventilation and a wide view.

Sliding Sash Windows: Vertical sliding windows that mimic the appearance of traditional sash windows, suitable for period properties.

Tilt and Turn Windows: Windows that can open inwards from the top for ventilation or swing open fully from the side for easy cleaning.

Bow or Bay Windows: Windows that protrude from the exterior wall, forming a bay in the room, and allow light to enter from multiple directions.

ROI (Return on Investment): The financial return or benefits received from an investment, such as energy savings and increased property value from installing new windows.

Conservation Area: A designated area of notable environmental or historical interest where changes to buildings are subject to specific controls to preserve its character.

Listed Building: A building officially recognised as being of special architectural or historical interest, subject to legal protections that restrict alterations.


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