Let's tabulate it.   @jack -0.04 °C.h-1  @SteamyTea -0.132 to -0.296 °C.h-1 can call that 0.21 °C.h-1  @haddock -0.3 °C.h-1  @MikeGrahamT21 -0.33  °C.h-1  @Nick Thomas -0.5 °C.h-1    So my old 1987 house, with some minor modifications, is petty good. I am not sure how much of that is to do with being a terrace, or small, or at a colder internal temperature, or a higher external temperature. My place is TF, so can we knock that 'thermal mass' nons