This case study describes upgrades to Scotstarvit Tower Cottage, a detached rural building owned by the National Trust for Scotland. The single-storey cottage is located near Cupar, Fife, adjacent to the monument Scotstarvit Tower. The refurbishment project demonstrates a range of energy efficiency upgrades that can be carried out in traditionally constructed buildings, with minimal or no loss of original fabric. The project involved the use of innovative materials, in particular loose-fill perlite wall insulation, and demonstrated the use of vapour-permeable materials and finishes. The project also included the installation of radiant heating.