Passivhaus project

New Passivhaus office building

Client: Raynsway Properties

Location: Leicester

Project: 560m2 office block

The Project

Interserve required a new two-storey office building to replace their old office building and accommodate their expanding East Midlands team.

The Challenge

Interserve required a building that would actively promote sustainability and was a low energy space. The new Passivhaus office was predicted to save £20,000 per year for Interserve, in comparison to their old premises. They predicted energy costs of the new building to be £2821.69 per year with annual CO2 emissions of 17.73 tonnes whereas their previous were costing £23,336.10 in energy bills per year and emitted 111.67 tonnes of CO2.

The Durisol system was chosen as it delivers very high levels of insulation and an airtight building fabric without any thermal bridges.

The Outcome

Completed within a year of being on-site, the two-storey 560m2 office block was constructed using Durisol blocks and PIR insulation. The building was clad in FSC-certified Thermowood cladding and had triple glazed windows with Levolux external blinds to the south façade.

The building achieved wall U-values of 0.12W/m2K with roof and floor values of 0.13W/m2K and an air tightness of 0.885m3/hr/m2 @ 50pa.

The completed building was the first carbon neutral Passivhaus commercial office in England. Interserve now benefit from low energy bills (a reduction of over 80% compared to their previous energy consumption) and are less dependent on the uncertain energy market.

Client Comment

We chose Durisol for its good U value and thermal performance and were not disappointed.