Energy Efficiency Improvements in a Modern Listed Building: The Herman Miller Factory
This case study is about making a 1970s steel framed building clad in glass fibre panels more energy efficient as part of the building’s adaptation to a new use.
About the property
The Herman Miller Factory is a Grade II listed former furniture factory situated next to the River Avon in the City of Bath World Heritage Site. It is also in the city centre conservation area. The factory was designed by Nicholas Grimshaw and built in 1976-7. The building is steel framed and clad in glass fibre panels.
About the adaptation
After the Factory closed the site was purchased by Bath Spa University as a new home for the Bath School of Art and Design. The building had been designed to adapt to change so future occupants could alter it to suit their needs. The University engaged Grimshaw, whose founder originally designed the building, to oversee the adaptation.
The University took the opportunity to improve energy efficiency while refurbishing the building. The existing roof was in poor condition and provided limited thermal performance. A new roof was installed with increased and improved insulation and the opportunity was taken to install photovoltaics (solar panels).
Single glazed windows were replaced with bespoke double glazed ones and rooflights were added on the north face of the building to increase natural daylight and reduce the need for artificial light. New insulation was installed behind the solid façade panels with a new inner timber lining protecting the existing panels and enclosing the additional insulation They also removed the original loading bay doors which had poor thermal performance. The services in the building such as hot water and heating systems were replaced.
What happened during the planning process?
The architects and University engaged with the local authority’s conservation officer and with the Twentieth Century Society during the pre-planning stages to enable them to comment on the project. This made the planning process much smoother as did using the original architect of the building to undertake the changes.
The University required listed building consent and planning permission from Bath and North East Somerset Council. The process for obtaining them was straightforward with regards to adaptations for energy efficiency. The flexible, original design of the building was part of its architectural significance, which enabled changes to be made to it, including changes to improve energy efficiency.
The local authority balanced the impact of the changes to the listed building against the clear public benefit that the reuse of the building has brought. Planning permission and listed building consent was granted in 2017.
The installation process
The installation process began in 2018 and was completed in 2020. The architects said working on the building was “an unusual challenge to adapt a listed building, when the listing is in part based on an innovative approach to flexibility.” During installation, they were mindful to ensure any energy efficiency adaptations were in keeping with the original design concept of the building and retain its character.
Impact and lessons learned
- The thermal performance of the building was significantly improved by the additional roof and facade insulation and replacement of single glazing with double glazing.
- The changes to the roof allowed for the installation of solar panels, which generate 10% of the power for the building.
- The energy saving measures contributed to enabling the building’s reuse and its future sustainability.
- The building has been transformed from a derelict factory to an art school with facilities for both students and the local community.
