Call us: 01773 300510

Heritage Windows: A Guide to Replacing Windows in Listed Buildings

Homepage > Heritage Windows > Heritage Windows: A Guide to Replacing Windows in Listed Buildings
Heritage Windows: A Guide to Replacing Windows in Listed Buildings - heritage windows in a listed cottage in Derbyshire

Heritage Windows: A Guide to Replacing Windows in Listed Buildings

Reading Time: 17 Minutes
Published on: June 8th, 2023

Read Now


Preserving the architectural heritage of listed buildings is a paramount responsibility for their owners. One crucial aspect of this preservation is the careful replacement of windows, striking a balance between retaining the building’s historic character and incorporating modern benefits. In this comprehensive guide to replacing windows in listed buildings, we will delve into the world of heritage windows, exploring the importance of their preservation and the considerations involved in finding the right replacements.

At Gowercroft, we are passionate about manufacturing award-winning timber windows and doors that excel in both performance and aesthetics. By utilising modern timbers like Accoya and Red Grandis, we offer solutions that enhance service life, improve thermal efficiency, and reduce maintenance requirements. Additionally, our use of LandVac vacuum glazing technology further enhances energy efficiency, with a center pane U-Value of 0.4 and whole unit values ranging from 0.9 to 1.3.

Join us as we embark on a journey to understand heritage windows, the significance of listed buildings, the criteria for replacement, and the innovative solutions that pave the way for preserving architectural heritage while embracing modern advancements.

Section 2: What Are Heritage Windows?

Heritage windows play a crucial role in maintaining the original look, character, and historical significance of listed buildings. These windows are designed to faithfully replicate the appearance of the original windows while incorporating modern performance features. Let’s delve into the definition, historical background, and the need for this unique window solution.

Definition of Heritage Windows

Heritage windows refer to replacement windows specifically designed for listed buildings. These buildings, recognised for their architectural or historical importance, require special attention when it comes to renovation and restoration. Heritage windows aim to closely match the original windows in terms of design, materials, and aesthetic details, while also offering enhanced functionality and energy efficiency.

Historical Background and Evolution

The concept of heritage windows emerged as a response to the need for maintaining the authenticity of listed buildings. Over the years, architectural styles and window designs have evolved, reflecting the trends and technological advancements of each era. Heritage windows are a testament to the craftsmanship of the past, paying homage to the architectural heritage while incorporating modern advancements in materials and construction techniques.

Initially, the replacement of windows in listed buildings was a challenging task, as traditional windows often lacked the energy efficiency and performance standards expected in contemporary times. However, with the advancements in manufacturing and materials, heritage windows now strike a perfect balance between preserving the original character and meeting the demands of modern living.

Preserving Traditional Aesthetics with Modern Performance

One of the key objectives of heritage windows is to maintain the traditional aesthetics of listed buildings. These windows often feature authentic design elements such as glazing bars, decorative moldings, and intricate details that reflect the architectural style of the period. By using modern timber materials like Accoya and Red Grandis, manufacturers like Gowercroft are able to enhance the service life, improve thermal efficiency, and reduce maintenance requirements of heritage windows. Furthermore, the application of microporous paints and varnishes adds an additional layer of protection while retaining the natural beauty of the timber.

While the preservation of traditional aesthetics is crucial, it is equally important to ensure that heritage windows meet contemporary performance standards. This includes considerations for energy efficiency, insulation, soundproofing, and security. Innovative technologies such as LandVac vacuum glazing have revolutionised the thermal efficiency of heritage windows, allowing for better insulation and reduced heat transfer without compromising on the appearance of single-glazed windows.

By combining the charm of traditional design with the benefits of modern materials and technologies, heritage windows enable owners of listed buildings to enjoy the best of both worlds. These windows not only contribute to the preservation of architectural heritage but also create comfortable and sustainable living spaces for generations to come.

In the following sections, we will explore in more detail the significance of listed buildings, the criteria for replacement windows, and the various materials and design considerations involved in the restoration process.

Understanding Listed Buildings

Preserving our architectural heritage is of paramount importance, and listed buildings play a vital role in safeguarding our shared history. In this section, we will explore what constitutes a listed building, the different grades assigned to them, and the legal requirements and restrictions associated with their preservation.

What Constitutes a Listed Building?

A listed building is a structure that has been recognised and protected for its special architectural, historical, or cultural significance. These buildings are considered to be of national importance and are legally protected to ensure their preservation for future generations. Listed status applies to both the exterior and, in some cases, the interior of the building, as well as any fixed structures within its curtilage.

Introducing the Different Grades of Listed Buildings

Listed buildings are categorised into three main grades, each signifying a different level of significance:

1. Grade I: Buildings of Exceptional Interest

   – Grade I listed buildings are deemed to be of exceptional architectural or historic importance on a national scale. They represent the pinnacle of our architectural heritage and include iconic structures such as cathedrals, castles, and stately homes.

2. Grade II*: Particularly Important Buildings of More than Special Interest

   – Grade II* listed buildings are considered to be particularly important and of more than special interest. They possess exceptional architectural or historic significance at a regional or local level. Many Grade II* buildings are unique or hold important historical associations.

3. Grade II: Buildings of Special Interest, Warranting Every Effort to Preserve Them

   – Grade II listed buildings are of special interest and warrant every effort to preserve their architectural or historic character. This is the most common grade of listed buildings, encompassing a wide range of structures, from cottages and townhouses to industrial buildings and barns.

Legal Requirements and Restrictions

The protection and preservation of listed buildings are governed by legislation and regulations. In England, Historic England maintains the statutory list of listed buildings, while similar organisations exist in Scotland, Wales, and Northern Ireland. It is illegal to alter, extend, or demolish a listed building without obtaining the necessary consent from the local planning authority.

Owners of listed buildings have a responsibility to maintain and preserve the historic fabric and character of their properties. Any proposed alterations, repairs, or additions must undergo a rigorous planning process, considering the impact on the building’s significance. Conservation officers and planning authorities are involved in assessing and granting consent for proposed works, ensuring that any changes are sympathetic to the building’s historic value.

Understanding the importance of listed buildings and complying with the legal requirements is essential for the preservation of our architectural heritage and the unique stories they tell.

To learn more about the designation of listed buildings, you can visit the Historic England website at

In the following sections, we will explore the reasons for replacement windows in listed buildings, the criteria for selecting suitable replacements, and the materials and design considerations involved in the restoration process.

Reasons for Replacement Windows in Listed Buildings

Listed buildings hold a significant place in our architectural heritage, but over time, the need to replace windows in these properties may arise. In this section, we will explore the reasons why owners of listed properties may need to consider window replacement. We will also discuss common issues associated with original windows and emphasise the importance of finding a balance between heritage preservation and improved functionality.

Preservation and Upkeep

Listed buildings often have windows that have stood the test of time, sometimes for centuries. However, despite their historical charm, these original windows can present various challenges in terms of maintenance and functionality. Over the years, factors such as weather exposure, wear and tear, and lack of proper upkeep can lead to decay, compromising the structural integrity of the windows.

Decay and Deterioration

One of the most common issues with original windows in listed buildings is decay. Traditional windows often feature timber frames that are prone to rot and insect infestation if not adequately protected and maintained. Decay not only compromises the aesthetics of the windows but also affects their performance, leading to air leaks, drafts, and moisture ingress.

Security Concerns

Another aspect that necessitates window replacement in listed buildings is security. Many original windows lack modern security features, making them vulnerable to intrusions. Upgrading to more secure and robust windows ensures the safety and protection of the building and its occupants without compromising its historical character.

Energy Inefficiency

Original windows in listed buildings often have single glazing, which provides limited insulation against heat loss and noise infiltration. As energy efficiency standards have evolved, the thermal performance of these windows may not meet modern expectations. Replacement windows can incorporate double or even triple glazing, significantly improving insulation, reducing energy consumption, and enhancing occupant comfort.

Balancing Heritage Preservation and Improved Functionality

When considering replacement windows in listed buildings, it is essential to strike a balance between preserving the building’s heritage and improving functionality. While the original windows contribute to the unique character of the property, it is crucial to address the practical needs of modern living. This balance can be achieved by carefully selecting replacement windows that closely replicate the original design and materials, while incorporating modern advancements in performance, security, and energy efficiency.

Manufacturers like Gowercroft specialise in crafting heritage windows that honour the traditional aesthetic while utilising innovative materials such as Accoya and Red Grandis. These modern timbers offer enhanced durability, improved thermal efficiency, and reduced maintenance requirements. Additionally, technologies like LandVac vacuum glazing can provide excellent insulation while maintaining the appearance of single-glazed windows.

By replacing windows in listed buildings with careful consideration for heritage preservation and improved functionality, owners can ensure the long-term sustainability and enjoyment of their cherished properties.

In the following sections, we will delve into the criteria for selecting suitable replacement windows, explore the various materials available, and discuss design considerations that are essential in the restoration process.

Criteria for Replacement Windows in Listed Buildings

When it comes to replacing windows in listed buildings, there are specific criteria set by planning authorities to ensure the preservation of the building’s heritage. In this section, we will explore the criteria that must be considered when selecting suitable replacement windows. We will also discuss the challenges associated with meeting these criteria while providing the modern benefits of improved performance and functionality. Additionally, we will emphasise the importance of retaining the original aspect, materials, and design of the windows in order to maintain the historical integrity of the listed building.

1. Retaining the Original Aspect:

The primary requirement for replacement windows in listed buildings is to retain the original aspect of the windows. Planning authorities aim to preserve the architectural character and appearance of the building, including its fenestration. This means that the replacement windows should closely resemble the original windows in terms of size, shape, proportions, and overall design.

2. Material and Design Considerations:

In order to maintain the authentic look and feel of the building, it is important to select materials that match the original windows. Traditional materials such as timber are often preferred for their historical accuracy and aesthetic appeal. Manufacturers like Gowercroft specialize in crafting heritage windows using modern timber options like Accoya and Red Grandis, which offer improved durability, thermal efficiency, and reduced maintenance requirements.

3. Compliance with Planning Authority Guidelines:

It is essential to consult with the local planning authority and obtain their approval before proceeding with window replacement in a listed building. The planning authority will have specific guidelines and requirements regarding the acceptable materials, design details, and overall approach to the replacement windows. Working closely with conservation officers and adhering to their recommendations will help ensure that the replacement windows meet the necessary standards for heritage preservation.

4. Balancing Modern Benefits with Heritage Preservation:

One of the challenges in replacing windows in listed buildings is balancing the desire for modern benefits, such as improved energy efficiency and security, with the need to preserve the building’s historical integrity. This can be achieved by incorporating modern technologies and techniques while staying true to the original design. For example, double or triple glazing can be installed within the appropriate window frame design to enhance thermal performance without compromising the appearance of the windows.

5. Consultation with Specialists:

Given the unique requirements and complexities associated with window replacement in listed buildings, it is advisable to seek the expertise of specialists in heritage windows. Companies like Gowercroft, with their experience in manufacturing award-winning timber windows and doors, can provide valuable guidance in selecting appropriate replacement windows that meet the planning authority criteria while offering modern benefits.

By carefully considering the criteria set by planning authorities, preserving the original aspect and design, and utilising suitable materials and technologies, it is possible to find replacement windows that strike a balance between heritage preservation and modern functionality in listed buildings.

In the next section, we will explore the materials and design considerations for heritage windows, including the benefits of using modern timbers and vacuum glazing.

Materials and Design Considerations

When it comes to heritage window replacements in listed buildings, selecting the right materials and considering the appropriate design details are crucial. In this section, we will discuss the materials commonly used in heritage window replacements, such as wood and UPVC. We will highlight the benefits and drawbacks of each material in terms of aesthetics, durability, and energy efficiency. Additionally, we will explore design considerations that focus on replicating ornate features and maintaining the architectural style of the building. Finally, we will reference a study conducted by Gowercroft in collaboration with Derby University, which investigates the environmental impact of different window types, showcasing the negative carbon footprint of timber windows compared to the damaging effects of aluminium and UPVC windows.

1. Wood

Wood is a traditional and popular material for heritage window replacements due to its authentic appearance and versatility. It can be crafted to match the original design and replicate ornate features, making it an ideal choice for listed buildings. Timber windows, especially when using modern timbers like Accoya and Red Grandis, offer enhanced durability, improved thermal efficiency, and reduced maintenance requirements. They can withstand the test of time while providing a timeless aesthetic. Furthermore, a study conducted by Gowercroft in collaboration with Derby University has shown that timber windows have a negative carbon footprint, making them an environmentally friendly choice.

2. uPVC

UPVC (unplasticised polyvinyl chloride) is a commonly used material for window replacements, including in heritage applications. While it may offer benefits in terms of cost-effectiveness and low maintenance, it often falls short in terms of matching the authentic appearance and charm of traditional windows. UPVC windows may not be suitable for buildings with strict preservation requirements, as they can lack the intricate details and visual appeal of timber windows. Additionally, UPVC is derived from non-renewable fossil fuels, and its production and disposal can have detrimental effects on the environment.

When choosing the material for heritage window replacements, it is important to consider the specific requirements of the listed building and its architectural style. While UPVC may have advantages in terms of cost and maintenance, it is essential to evaluate the impact on the overall aesthetics and historical integrity of the building.

Certainly! Here’s an additional section discussing aluminium and steel window frames:

3. Aluminium and Steel:

Aluminium and steel are materials that are sometimes considered for heritage window replacements, particularly in buildings where a more modern aesthetic is desired or where strict preservation guidelines allow for their use. These materials offer unique characteristics and benefits.

Aluminium frames are known for their sleek and contemporary appearance. They are lightweight, durable, and require minimal maintenance. Aluminium windows can be powder-coated in a variety of colours, providing flexibility in design choices. However, when it comes to replicating the traditional look and feel of heritage windows, aluminium may not be the ideal choice, as it lacks the warmth and authenticity of materials like wood. Additionally, the production of aluminium frames requires a significant amount of energy, and their thermal performance may not be as efficient as other materials.

Steel frames are renowned for their strength and durability, making them a suitable option for larger or more structurally demanding window openings. They can provide slim sightlines and large expanses of glass, creating a unique architectural statement. Steel windows often have a distinctive industrial aesthetic that can complement certain styles of listed buildings, such as converted warehouses or modernist designs. However, it’s important to consider that steel frames require regular maintenance to prevent corrosion, and their thermal efficiency may be lower compared to other materials unless additional thermal breaks or insulation measures are incorporated.

When considering aluminium or steel frames for heritage window replacements, it’s crucial to evaluate their compatibility with the building’s architectural style and preservation requirements. While these materials offer contemporary design options and structural benefits, they may not always align with the traditional aesthetic and historic integrity that many listed buildings seek to preserve.

By understanding the characteristics and considerations associated with different materials like wood, UPVC, aluminium, and steel, property owners can make informed decisions about the most suitable option for their heritage window replacements. Balancing the preservation of the building’s character with improved functionality and energy efficiency will ensure a successful outcome.

In the following section, we will explore the benefits of vacuum glazing and its application in heritage windows, shedding light on its contribution to energy efficiency while preserving the original aesthetic.

Design Considerations

Design plays a vital role in heritage window replacements. The goal is to replicate the original features, proportions, and architectural style of the windows. This includes paying attention to details such as panel configurations, glazing bars, decorative mouldings, and hardware. By closely adhering to the original design, replacement windows can seamlessly integrate into the building’s façade, preserving its historical character.

Ornate features, such as arched tops, intricate mullions, and traditional glazing techniques, should be carefully replicated to maintain the authenticity of the windows. The use of modern technologies, such as vacuum glazing, can help achieve improved energy efficiency without compromising the visual aspect of the windows.

Gowercroft has conducted a study in collaboration with Derby University to assess the environmental impact of different window types. This study provides valuable insights into the negative carbon footprint of timber windows, highlighting their sustainable and eco-friendly nature. In contrast, aluminium and UPVC windows are shown to have damaging effects on the environment. This information further supports the case for choosing timber windows for heritage replacements in listed buildings.

Read the study here:

In the following section, we will delve into the benefits of vacuum glazing and its application in heritage windows, further exploring its impact on energy efficiency and preserving the original aesthetic.

Energy Efficiency Solutions for Heritage Windows

Preserving the historical character of listed buildings is essential, but it is equally important to address the energy efficiency challenges posed by traditional single-glazed windows. In this section, we will explore the solutions available to improve the energy efficiency of heritage windows while meeting the criteria set by planning authorities.

1. Slim Double Glazing

One approach to enhancing the thermal performance of heritage windows is the use of slim double glazing. These units feature a narrower cavity between the two panes of glass, typically around 4mm, which reduces the overall thickness of the window. Slim double glazing aims to strike a balance between energy efficiency and maintaining the appearance of single-glazed windows.

While slim double glazing offers some benefits, it can come with drawbacks. The narrow sealant area poses a challenge in ensuring long-term air-tightness, increasing the risk of seal failure over time. Moreover, the double reflection caused by standard double glazing units can be visually disruptive and may not meet the aesthetic requirements of heritage window replacements. Planning authorities often hesitate to approve slim double glazing units due to these limitations.

2. Vacuum Glazing

Emerging as a promising energy-efficient solution for heritage windows, vacuum glazing has gained traction in recent years. Vacuum glazing utilises a vacuum-sealed cavity between two glass panes, minimising heat transfer and enhancing thermal insulation. This technology allows for an incredibly narrow gap between the panes, as little as 0.2mm, providing the appearance of single-glazed windows while delivering excellent energy efficiency.

Vacuum glazing addresses the concerns associated with double reflection and the bulkiness of standard double glazing units. The slim profile and minimal reflection of vacuum glazing closely resemble the aesthetic of original single-glazed windows, making them more likely to be approved by planning authorities for heritage window replacements.

Gowercroft has been at the forefront of utilising vacuum glazing in heritage window solutions. Their partnership with LandVac, a leading manufacturer of vacuum glazing, has enabled them to offer heritage windows with a center pane U-value of 0.4 and whole unit values of 0.9 to 1.3. This advanced technology ensures optimal thermal efficiency while preserving the authentic look of listed buildings.

By embracing vacuum glazing technology, heritage window replacements can achieve the dual goals of meeting energy efficiency requirements and maintaining the original aesthetic of listed buildings. This innovative solution opens up new possibilities for property owners seeking to upgrade their windows without compromising the historical integrity of their structures.

In the next section, we will delve into the design and customisation options available for heritage windows, highlighting the importance of replicating the original aspect and architectural details of the windows.

Navigating Planning Permission:

Obtaining planning permission for heritage window replacements in listed buildings is a crucial step in ensuring compliance with preservation guidelines and regulations. In this section, we will guide you through the process and provide tips for engaging with local planning authorities and conservation officers.

1. Understand the Guidelines:

Before embarking on any window replacement project, familiarise yourself with the specific guidelines and requirements set by your local planning authority. These guidelines outline the criteria for acceptable heritage window replacements, including aspects such as materials, design, and energy efficiency. Take the time to carefully review these guidelines to ensure your proposed replacements align with the preservation objectives.

2. Consult Conservation Officers:

Engaging with conservation officers early in the planning process is highly recommended. Conservation officers have a deep understanding of local heritage and preservation goals, and their insights can prove invaluable. Seek their advice and involve them in discussions regarding the proposed heritage window replacements. Their expertise will help you navigate the intricacies of the planning process and increase the chances of obtaining approval.

3. Prepare a Detailed Proposal:

When submitting your planning application, provide a comprehensive proposal that demonstrates your understanding of the building’s heritage value and your commitment to preserving its character. Include detailed plans, drawings, and specifications of the proposed window replacements, highlighting how they will replicate the original aspect and design. Clearly articulate the energy efficiency benefits and explain how the replacements align with the criteria outlined by the planning authority.

4. Showcase Successful Case Studies:

Support your planning application with successful case studies that showcase heritage window replacements in similar listed buildings. Highlight examples where the proposed replacements successfully achieved a balance between preserving the heritage and improving functionality and energy efficiency. This evidence can strengthen your argument for approval and provide assurance to the planning authority that your proposed replacements are in line with best practices.

5. Collaborate with Experienced Suppliers:

Working with experienced suppliers and manufacturers of heritage windows, such as Gowercroft, can significantly enhance your chances of obtaining planning permission. Suppliers who specialise in heritage window replacements understand the complexities of the planning process and can offer expert advice on materials, design, and energy efficiency solutions. Their knowledge and expertise can help you navigate potential challenges and ensure your proposals meet the requirements of the planning authority.

Remember, the planning permission process for heritage window replacements can be complex and time-consuming. Patience, collaboration, and open communication with the planning authority and conservation officers are key to a successful outcome. By following these tips and best practices, you can increase the likelihood of obtaining approval and proceed with your heritage window replacement project.


Heritage windows play a vital role in preserving the architectural heritage of listed buildings. They not only maintain the original character and aesthetic appeal but also contribute to the overall preservation of our cultural heritage. Throughout this guide, we have explored the significance of heritage windows, the challenges of replacing them, and the considerations involved in navigating the planning permission process. 

It is essential to strike a balance between preservation and modernization when it comes to heritage window replacements. While the need for improved energy efficiency and functionality is evident, it should not come at the expense of the building’s historical integrity. By carefully selecting materials, replicating design elements, and ensuring compliance with planning authority criteria, it is possible to achieve a harmonious blend of tradition and innovation.

When embarking on a heritage window replacement project, it is crucial to seek the expertise of reputable suppliers and professionals specialising in this field. Companies like Gowercroft, known for their award-winning timber windows and doors, can provide valuable guidance and high-quality products that meet both preservation requirements and modern performance standards. Their use of modern timbers like Accoya and Red Grandis, along with LandVac vacuum glazing, ensures enhanced service life, thermal efficiency, and reduced maintenance.

Preserving our architectural heritage is a collective responsibility, and by choosing the right materials, engaging with conservation officers, and following best practices, we can contribute to the long-term preservation of listed buildings. Whether you are a property owner, architect, or heritage enthusiast, investing in heritage window replacements is a significant step towards safeguarding our cultural legacy.

We encourage you to explore reputable suppliers and professionals specialising in heritage window replacements to ensure the success of your project. By working together, we can protect and celebrate the unique charm and historical value of our listed buildings for generations to come.

Heritage Window Case Studies

Find out more about our Heritage Windows