24 St James’s Square

AET Flexible Space was specified to supply its innovative CAM-V underfloor air conditioning (UfAC) system for the refurbishment of 24 St James’s Square, completed in early 2020.

The design brief was to maximise floor-to-ceiling heights and enhance the double aspect interior. One of the key challenges was the need to preserve key architectural features, whilst at the same time providing, flexible, modern, premium office space.

These needs could not have been met using a conventional overhead system, which would have taken up valuable headroom and created awkward junctions where window heads met suspended ceiling grids or exposed services.

Using an underfloor air conditioning system enabled the architects, BLDA, to eliminate ceiling-based services allowing for a plasterboard ceiling to be installed tight against the soffit and down stand beams. Thanks to the AET system, key architectural elements of the building were preserved, as well as increasing natural light levels and enhancing the striking double-aspect
interior.

“The AET downflow units promptly stood out as the obvious candidate for several reasons, including having the absolute minimum requirement for floor void height, and offering excellent distribution of cooling, heating and ventilation evenly across the whole floor whilst reducing energy consumption.” – M&E Consultant, Vic Holloway (Edward Pearce LLP).

AET’s UfAC system’s make use of the space beneath a raised access floor to create a ventilation path, eliminating the need for ceiling-based mechanical services helping to maximising the floor to ceiling heights creating a brighter and more and airy office environment.

A mix of CAM-V22 & 33 units were installed across the eight floors of office space. Roof mounted high efficiency heat pump units serve the refrigerant coils in each CAM’s. Conditioned air is delivered into the space via AET’s market leading TU350 slimline Fantile™ units which sit 160mm within the floor void.

To avoid unwanted grilles at high-level AET designed bespoke floor extract grilles that look identical to a Fantile™ units, to allow room air to be extracted directly from the floor void enabling the interior aesthetic to remain consistent and simplify duct routes within the buildings core. Common complaints from staff, prior to the refurbishment, were variations in temperature across the office space, high level cold draughts and a lack of natural daylight light. An UfAC solution however, provides greater individual control of localised temperature, unobtrusive movement of air and makes for a more comfortable, brighter working environment.

The 24 St James’s Square project has already won the “Best Office Architecture London” award at the 2019 International Property Awards and has very recently been awarded ‘Retrofit Project of the Year’ at the H&V News Awards 2020. The building is being let as Grade A office space by BNP Paribas Real Estate who advised the developer, Misland Capital, to consider AET’s system’s based on their positive experience with 28 Saville Row which AET completed in 2014.