20 Fenchurch Street

20 Fenchurch Street, known as "The Walkie-Talkie," is a 100,284 m² office tower in the City of London, completed in 2014. The building spans 37 floors plus a three-story public sky garden at its crown and is managed by Savills on behalf of the landlord, with multiple corporate tenants occupying the office floors. It operates on 100% renewable electricity, supplemented by roof-mounted photovoltaic panels, and is equipped with a central BMS, gas-fired heating, cooling towers, and a DHW system.

Through participation in the 2022–2023 CUBE UK competition, 20 Fenchurch Street achieved almost 32% energy savings, and had the largest gross savings of any building in the competition, placing second overall and generating an estimated £2.27 million in cost savings. The result was driven by close collaboration between property managers, tenants, and engineering teams, coordinated through monthly Green Team meetings.