SoftTone - the attentuated window; SoftTone - the attentuated window;

SoftTone, London

SoftTone: a window innovation that lets fresh air in but keeps noise out

SoftTone is a new window product created by Arup, and developed through our Venturing initiative. It provides a solution to help create efficient and sustainable spaces through improved ventilation and acoustics; saving energy, money and making buildings more user-focused. SoftTone has been brought to the European market through a partnership with manufacturer Reynaers, and is now being specified and installed on building projects.

Natural ventilation is becoming a growing challenge. With many commercial offices and residential buildings in urban environments located by busy roads, they are frequently relying on mechanical cooling to meet acoustic and overheating regulatory drivers. The result is higher operational costs and increased energy usage.

What if there was an alternative method to let fresh air in whilst keeping noise out?

SoftTone has made this a reality. The parallel-opening window system uses an intelligent combination of materials and geometry to minimise noise levels while enhancing natural ventilation to create quieter, healthier and more sustainable spaces for those living and working in modern urban buildings.

As part of our integrated building services, we can help realise the low-energy and low-carbon potential of buildings across the built environment. 

Project Summary

9dB noise reduction over a normal window

£6,300savings on mechanical equipment costs for 2-bed apartment

Ensuring residential and office buildings provide comfortable and practical environments is one of a series of challenges for the construction industry, which is why building products that help to limit the impact of typically noisy environments are key. Together with Arup, we’re proud to have developed an innovative and sustainable solution which does just that. ” John McComb Technical Director at Reynaers UK

The design

Rather than a traditional window opening, SoftTone utilises a parallel opening system to offer a greater open area per square metre. With the addition of sound absorption foam, it delivers greater acoustic performance compared to traditional opening types. Aluminium extrusions have been adapted to integrate the sound absorption material into the frame and sash of an existing window system, maintaining the window’s appearance while improving performance.

In practice, the design of SoftTone enables architects to include a greater volume of glazing into their designs, without fear of compromising aspects which either contribute to the building’s performance, or the comfort and enjoyment of those living within it.

Improving natural ventilation

With its carefully designed interface between the frame and sash, SoftTone is able to provide 0.6 square metres of ventilation gap (based on a 2m x 1m window), delivering effective ventilation and preventing a room from overheating.

By increasing natural ventilation with this parallel opening system, buildings and their occupants become less reliant on mechanical systems to cool internal spaces – something that has previously compromised the sustainable performance of many urban buildings. Including SoftTone in developments directly contributes to the decarbonisation of buildings, improving the living and working environment for all occupants.

SoftTone parallel opening window ventilation SoftTone parallel opening window ventilation
SoftTone provides greater acoustic performance and improved ventilation compared to a traditional window opening,

Reducing noise

In addition to its sustainability credentials, the truly leading aspect of SoftTone’s innovative design comes from its ability to reduce external noise when a window is open.

Naturally, an open window allows noise to pass through into homes and workplaces creating disturbances for occupants. By including SoftTone technology in buildings, indoor sounds levels can be reduced by 9dB more than a traditional open window, significantly decreasing the external noise and creating more comfortable spaces for occupants.

The Arup team has been a great development partner, not only bringing insights on technological aspects but also in understanding the value creation in the complex network of the building industry. This has resulted in Softtone, an energy saving and sustainable solution that we are able now to distribute through our existing network. ” Michel Van Put Chief Product Officer (CPO) at Reynaers Aluminium

Implementing SoftTone in developments

Our client was developing a major residential site in Central London, UK, beside a busy railway, and struggling to balance planning resulations based on noise levels with sustainability targets. 116 apartments were determined to be of high acoustic risk, worsened by overheating risks due to no openable windows. Reynaers and Arup worked in collaboration with the developer’s team to realise the benefits of SoftTone within the development.

A new acoustic study coupled with a demonstrator unit within the development’s innovation hub allowed the client to see and experience the benefits first-hand. The study demonstrated that including SoftTone in the development reduced the apartments at high acoustic risk to zero. The removal of mechanical cooling from 30 apartments provided a carbon saving of 0.5 tonne/CO2/yr – a 9% saving on mechanical system operation costs. The projectis set to complete in late 2021.

As we look to a more sustainable future for our urban living and working requirements, the buildings which define our skylines must be designed to maximise natural ventilation. Windows are the natural starting point in this journey and SoftTone enables architects and engineers to introduce greater volumes of glazing into their designs, without compromise.

More information can be found on the Reynaers website.