CASE STUDY | LARK RISE RISE TO THE CHALLENGE A Passivhaus Plus home in the Chiltern Hills establishes the building as a power station concept and shows the viability of an electrical grid powered by renewable energy. Andy Pearson reports W hen Justin Beres clients said they wanted a lowenergy home, the architect convinced them that Passivhaus (PH) would meet their aspirations. We went on a PH tour of Switzerland and Austria, and they both got the Passivhaus bug, Bere says. Then, while bere:architects was developing the design for their home, the Passivhaus Institut launched Passivhaus Plus, a new certification category that recognises the production of onsite renewable energy by passive buildings. When Bere told his clients about the enhanced category, they decided a Passivhaus Plus home would better meet their aspirations and it did. Finished in October 2015, Lark Rise was the first completed Passivhaus Plus scheme in the UK. This pioneering, ultra-lowenergy, all-electric contemporary home incorporates a large photovoltaic (PV) array and a powerful battery, making it one of the most advanced, high-performance homes in England. Two years of monitoring show that the scheme generates more than twice as much energy as it consumes in a year and exports to the National Grid around 10 times the energy that it imports each year. With credentials as impressive as this, it was no surprise that the scheme won the Residential Project of the Year category at this years CIBSE Building Performance Awards. The judges described the house as a groundbreaking development that, if adopted more widely, would challenge the need to fulfil energy demand through additional Grid capacity. The 175m2 detached homes energy performance is all the more impressive given that the two-storey Passivhaus faces north-west, with limited opportunity to exploit PROJECT TEAM Architect: bere:architects Mechanical and electrical services: Alan Clarke Ventilation detailed design: Green Building Store Structural design: Techniker Design and installation of the PV solar array: Darke and Taylor Battery sizing: Energelio Passivhaus Plus certification was granted by the Passivhaus Institut, Darmstadt, Germany, in November 2017; the certifying agent was Kym Mead, of Mead Consulting. 22 May 2019 www.cibsejournal.com CIBSE May19 pp24-28 Lark Rise.indd 22 26/04/2019 17:00