Three Seas, a specialist charity that supports the provision of community housing for Cornwall's local communities, are renovating a grade II listed building to provide vital low-rent flats. This project is currently in detailed design.

We are providing mechanical services design, as well as oversight of the building fabric proposals and PHPP modelling. Many standard solutions would not work for this project; each flat is only 30-50 m2 and the existing layouts are challenging. There have also been significant conservation limitations as the site is highly visible and of significant interest locally and among conservation officers. This coupled with the extensive damp due to years of neglect meant that we have to have much greater engagement with the project.

Due to the limitations we investigated a much broader range of heating and hot water options, from communal ground source heating to mini-split heat pumps - all standard solutions but not commonly deployed in this context. To communicate the wide range of considerations we created a detailed schedule to compare the options including capital costs, running costs and upfront carbon impacts with an emphasis on robustness and usability, from this a strategy was developed.

Balancing fabric upgrades with services performance is critical for these kind of projects; as well as undertaking extensive calculations we leaned heavily on our experience of real-world performance.