Originally built in the 1970s, 90 Long Acre is a 240,000 sq ft landmark in Covent Garden, London. Northwood Investors wanted to repurpose the iconic but obsolete Brutalist building, designed by noted architect Richard Siefert, to revitalise existing office areas and floor space, upgrade its performance and provide new public space and retail opportunities at ground level. 

Working closely with the architect Gensler, Arup provided a series of interventions to retain as much of the existing structure as possible while reducing operational energy use in the building by over 70%, enabling it to outperform new-build energy standards. We targeted WELL Platinum certification and Fitwel 3 Star – the highest levels on the leading international frameworks for health and wellbeing in buildings.

With substantial whole life carbon savings, wellbeing interventions, natural ventilation, biodiverse terraces, public spaces and green travel features, the Acre has achieved a SCORS: A+ and is on track to achieve BREEAM Outstanding, 4.5 NABERS UK Star and RIBA 2030 embodied carbon targets on completion. 

Transforming energy performance in a 1970s building 

‘Infill’ extensions make the building’s thermal envelope more effective, reducing heating and cooling loads. Other passive improvements include internal insulation fitted to existing façades and high-performance new façades. A new, all-electric heating and cooling system uses high-efficiency pumps that reclaim heat for hot water. Artus fan coil units will condition Cat A space during extreme temperatures, taking up less office space and using 50% less power than traditional units. A smart platform allows real-time energy analysis and predictive maintenance of the plant, along with live monitoring of window operations.

We look forward to giving this Richard Seifert landmark a new lease of life. We’ve listened to the needs of contemporary business and designed The Acre to be Covent Garden’s greenest and healthiest workplace, reducing embodied and operational carbon and placing employee wellness at its heart.

Richard Strachan

Senior Vice President of Asset Management, Northwood Investors

Prioritising health and wellbeing 

The Acre targeted WELL Platinum certification and Fitwel 3 Star – the highest levels on the leading international frameworks for health and wellbeing in buildings. It features openable windows on every façade, allowing office workers to control internal temperatures for their comfort; extensive greenery; over 350 cycle spaces and a new pedestrian route through the building; spectacular roof terrace views; a reshaped ground floor opening up public access and adding retail space, connecting the building to the wider Covent Garden area. A ‘frangible’ atrium roof system is designed to disintegrate in a controlled fashion at high temperatures, so heat escapes from the building. This design also allows existing floors to be connected to the atrium, an intrinsic part of the natural ventilation strategy.  

Making the greatest sustainability impacts 

Arup led the sustainability strategy for the Acre starting with a UN Sustainable Development Goals workshop to identify the greatest potential environmental and social benefits at the outset. The decision to retain and reimagine the existing building halved embodied carbon, compared to a previously consented new-build scheme. With substantial whole-life carbon savings, wellbeing interventions, natural ventilation, biodiverse terraces, public spaces and green travel features, the Acre has already achieved a SCORS: A+ and it is on track to achieve BREEAM Outstanding, 4.5 NABERS UK Star and RIBA 2030 embodied carbon targets on completion.

Sustainability has been at the heart of the design of the Acre. Our analysis helped provide spaces that reflect wellbeing needs as well as sustainability needs - tying them both together.
Partners & collaborators

Gensler