Turning an iconic building into one of the healthiest and greenest developments in Central London

When Northwood Investors wanted to repurpose an iconic but obsolete Brutalist building, designed by noted architect Richard Siefert, they approached trusted advisor Arup for multidisciplinary services. Working closely with the architect, Gensler, we engineered a series of interventions to retain as much of the existing structure as possible, while transforming building performance.

Originally built in the 1970s, and formerly known as 90 Long Acre, the Acre is a 240,000 sq ft landmark in Covent Garden, London. Set to complete in 2023, the refurbishment will revitalise existing office areas, add floor space, upgrade the building’s performance and provide new public space and retail opportunities at ground level.

How do you transform energy performance in a 1970s building?

Impactful interventions are set to reduce operational energy use in the building by over 70%, enabling the refurbished older building to outperform new-build energy standards.

‘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. During extreme temperatures, Cat A space will be conditioned via Artus fan coil units, an award-winning technology developed by Arup, which uses 50% less power than traditional units. Their smaller dimensions also create an extra 150mm of floor to ceiling height, maximising the value of the Cat A office space.

The Acre will be fitted with a smart platform that allows real time energy analysis and predictive maintenance of the plant, along with live monitoring of window operations. This will give the property team and occupiers valuable insights and empower them to manage the building for efficiency and wellbeing.