Four-month long ethnographic study conducted by the University of Durham in 2016 and involving building professionals, planners and homeowners involved in the renovation and retrofit of buildings of attributed historic value in the Cotswolds. The research suggests that the uptake of energy-efficient technologies is significantly determined by assessments of ‘appropriateness’ that involve various intersecting considerations about the significance of a building’s past. Understandings of aesthetic, material and historic continuity are afforded different importance in different contexts and by different people, framing distinct understandings of the degree and kind of change that is consistent with maintaining ‘character’ and ‘authenticity’.