Windows can have a significant impact on how effectively a property retains heat. Older or poorly insulated windows can contribute to heat loss, higher energy consumption, and uncomfortable indoor temperatures.
So, what are the best windows for heat insulation? For modern residential projects, energy efficient window systems can help reduce heat loss while supporting better building performance and year-round comfort.
For property developers, landlords, installers and specifiers, choosing the right window means considering a range of factors. Glazing, frame materials, airtightness and installation all influence the performance of energy efficient roof windows.
A window’s thermal performance depends on how effectively its different components limit heat transfer between the inside and outside of a building.
Glazing is one of the most important considerations. Double and triple glazing can provide greater insulation than single glazing, while Low-E coatings and inert gas fillings can further improve performance.
The frame material also affects thermal efficiency. Timber has naturally insulating properties, while PVC can provide effective thermal performance alongside resistance to moisture. Dakea’s Better Energy PVC combines an energy efficient glazing system with a PVC frame and achieves a U-value of 1.1 W/m²K.
Airtight seals are another important consideration. Poorly sealed windows can create draughts and allow warm air to escape, reducing the effectiveness of other insulation measures.
Finally, installation quality is essential. Even a high-performance window may not achieve its intended thermal performance if it isn’t correctly fitted and integrated with the surrounding insulation.
The glazing specification plays a major role in determining how well a window retains heat.
Double and triple glazed windows use multiple panes separated by insulated spaces. These spaces can contain inert gases such as argon or krypton, helping to slow heat transfer through the glass.
Triple glazing can provide an additional level of insulation where higher thermal performance is required. The Dakea Ultima Energy uses triple glazing and krypton gas to achieve a U-value as low as 0.99 W/m²K, making it a suitable option where thermal performance is a key consideration.
Low-emissivity, or Low-E glass, can also help improve thermal performance. Its low-emissivity coating reflects heat back towards the interior, helping to reduce the amount of heat escaping through the glazing.
The right glazing can also help manage solar heat gain during warmer periods, supporting more comfortable temperatures throughout the year.
Glazing isn’t the only part of a window that affects heat insulation. The frame can also influence how effectively heat is retained.
Timber has naturally insulating properties and can provide an effective thermal barrier. Dakea’s range of wooden roof windows offers timber frame options for projects where both thermal performance and a traditional appearance are important.
uPVC roof windows offer another option, combining thermal performance with excellent resistance to moisture. Dakea’s Better Energy PVC roof window combines a moisture-resistant PVC frame with energy efficient glazing, making it particularly suitable for areas such as kitchens and bathrooms.
The construction of the frame is also important. Insulated frame technology can help reduce heat transfer through the window structure, complementing the performance of the glazing.
When comparing energy efficient window systems, it is therefore important to consider the performance of the complete window, rather than focusing on the glazing alone.
Choosing energy efficient roof windows can contribute to the wider energy efficiency and comfort of a property.
Energy efficient glazing, insulated frames and effective seals can help minimise heat transfer through the window, helping to keep warmth inside during colder months.
For example, the triple glazing and insulated construction of the Ultima Energy are designed to reduce heat transfer and support the thermal performance of the building.
When less heat escapes through windows, heating systems may need less energy to maintain a comfortable indoor temperature. This can help reduce energy consumption and heating costs over time.
Good thermal performance can help create more consistent indoor temperatures, reducing cold spots and draughts during winter. Appropriate glazing can also help manage solar heat gain during warmer weather.
Dakea’s Vision Energy is a fixed roof window designed with energy efficiency in mind, making it an option where additional natural light and views are required alongside thermal performance.
Energy efficient window systems form part of the wider building envelope, so their thermal performance should be considered alongside insulation, ventilation and other elements of the building specification.
For developers and specifiers, selecting appropriate windows can therefore contribute to the overall energy performance of a new build or refurbishment project.
Read more about how to reduce heat loss through windows.
There isn’t one solution that will be suitable for every project. The best windows for heat insulation will depend on the building, roof construction, room use and required thermal performance.
For new residential developments, roof windows should be considered as part of the initial specification. The required U-value should be assessed alongside the roof construction and insulation to ensure the windows complement the wider building envelope.
Dakea’s roof window range includes different glazing and frame options, allowing developers and specifiers to select a solution suited to the requirements of the project.
Thermal performance is particularly important when converting a loft into an occupied living space. New roof windows should work alongside upgraded roof insulation rather than creating a weak point in the building envelope.
Consider glazing, U-values, ventilation and the intended use of the room when selecting roof windows for a loft conversion.
Replacing older roof windows can provide an opportunity to improve thermal performance as part of a wider refurbishment.
For landlords and property owners, upgrading roof windows alongside insulation and other energy efficiency measures can help improve the comfort and overall performance of an existing property.
For heritage and conservation projects, thermal performance may also need to be balanced with the appearance of the window. Dakea’s Conservation roof window combines a traditional timber appearance with modern glazing and insulation technology.
Choosing an energy efficient roof window is only part of achieving good thermal performance. Correct installation is essential to ensure the window performs as intended.
Poor installation can create gaps around the window, compromise airtightness, and allow heat to escape. It can also contribute to cold spots and moisture-related issues such as condensation.
Roof windows should be installed according to the manufacturer’s instructions and properly integrated with the surrounding insulation and roof structure.
Installation accessories such as flashing, underfelt collars and vapour barriers can also help create a properly sealed installation.
See our roof window installation guidance for more information.
Dakea roof windows are designed to support the thermal performance requirements of modern residential projects, combining high-performance glazing, insulated frame technology and effective sealing to help reduce heat loss.
From the triple-glazed Ultima Energy to the moisture-resistant Better Energy PVC and fixed Vision Energy, the range includes solutions for different project and specification requirements.
For refurbishment and conservation projects, our Conservation roof windows combine a traditional appearance with modern thermal performance.
Whether you’re specifying windows for a new build, loft conversion or refurbishment, selecting the right combination of glazing, frame construction and installation can help reduce heat loss, improve thermal efficiency and create more comfortable interiors.
Explore the Dakea roof window range or contact our team for support with your project specification.
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