Aluminium vs uPVC: Why aluminium is best for Multi-Residential builds

9 September 2024 / 4 min read / Windows & doors, Thermal

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When designing multi-residential projects, architects face decisions that significantly impact the long-term quality, aesthetics, and functionality of the buildings. One crucial choice is the type of window frames to specify. UNO Thermal aluminium windows offer significant advantages, particularly in terms of durability, thermal stability, and design flexibility.

In this article, we’ll explore the key differences between aluminium and uPVC windows and why specifying UNO Thermal aluminium windows in your projects is a smarter choice.

Comparing Thermal stability for Multi-Residential projects

uPVC windows are known for good thermal insulation. However, they have a significant drawback: thermal expansion.

In warmer temperatures, uPVC can expand considerably, causing issues with the functionality of the windows and doors. According to a study by Tangram Technology, uPVC expands 2.5 times the rate of aluminium and 5 times the rate of steel. Also of note is the maximum allowable serviceability temperature for uPVC is 60ºC and the melting point is around 160ºC.

For architects working on multi-residential projects in New Zealand, the expansion of uPVC frames can be a significant factor to consider. This expansion may affect regular use, it can lead to difficulty in opening and closing windows, leading to air leaks, water ingress, and decreased energy efficiency over time, and in extreme cases, it may cause the frames to warp or crack, leading to costly repairs and replacements. Ensuring the long-term durability of windows is crucial not only for maintaining occupant satisfaction but also for preserving the resale value of the property. High-quality, durable windows contribute significantly to the long-term value of a home, making them an essential consideration in any project.

To avoid these issues, consider specifying UNO Thermal aluminium windows in your projects. 

Explore our range of UNO aluminium windows and doors to find the perfect solution for your needs.

The UNO Thermal aluminium advantage: stability, strength, and aesthetic flexibility

UNO Thermal aluminium windows are far less susceptible to thermal expansion, with uPVC expanding 2.5 times more than aluminium (darker colour uPVC frames can expand more due to additional solar heat absorption). Aluminium is a metal, and while it does conduct heat, modern aluminium windows are designed with thermal breaks—insulating materials inserted between the inner and outer frames to reduce heat transfer. This innovation allows aluminium windows to offer excellent thermal performance while maintaining their structural integrity, with temperature changes.

Aluminium windows also offer greater durability when compared to uPVC, outlasting uPVC by a significant margin, which is a crucial consideration when specifying a new build.

The strength of aluminium windows also allows for slimmer profiles, which means larger glass areas and more natural light for the building’s interior. On a 1200mm by 1800mm window, you can gain around 10% extra visible glass area by using an aluminium frame instead of uPVC (or the aluminium window size can be reduced by 10% to obtain the same visible glass area). This is particularly advantageous in multi-residential projects where maximising light can improve the living experience for residents. 

blog photoPhoto by Diakrit

Another significant advantage of aluminium windows is their design flexibility. They can be powder-coated in various colours, allowing architects to achieve the exact aesthetic they desire. UNO offers a range of key colours that cater specifically to the New Zealand market, ensuring that your project not only meets functional requirements but also stands out visually.

Explore our aluminium colour options here.

Environmental impact: Aluminium vs. uPVC

In today’s world, sustainability is a growing concern for architects and developers. Aluminium is a highly recyclable material, with around 75% of all aluminium ever produced still in use today. Recycling rates in the building industry can exceed 90% and recycled aluminium requires only around 5% of the energy needed to produce new aluminium. This recyclability significantly reduces the environmental footprint of aluminium windows, making them a more sustainable choice. The estimated median service life of aluminium windows compared to uPVC is almost double according to a life cycle assessment conducted in the UK.

On the other hand, uPVC production involves toxic chemicals, and its disposal poses challenges since it is not easily recyclable in New Zealand (recycled content used across Europe for new uPVC profiles is around 10%). 

Thermal Profile

Conclusion: UNO Thermal aluminium is the best choice

For architects working on multi-residential projects, who prioritise sustainability, UNO Thermal aluminium windows are clearly the better choice.

UNO Thermal’s superior durability, thermal stability, resistance to UV rays, and design flexibility make it the ideal choice for ensuring the longevity and quality of your projects.

To specify UNO’s aluminium windows and doors easily, check our profile at Masterspec and ensure your project benefits from our end-to-end solution. 

For more detailed specifications and technical information, visit our Resources page.

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