Heat rises, so the top floor apartment is often the warmest in winter, sometimes even unpleasantly so. Building heating systems, even with individual room thermostats, are often unable to properly cope with variations in difrerent rooms.

The flat we had in Engleberg used underfloor heatingin the main living area throughout, but was always too hot until I replaced the living room carpet with cork-backed wood laminate flooring. the extra insulation was perfectly matched to stop the heat penetrating too much.

Around that time I also converted the attic into a third bedroom with no heating in it at all, but that was always pleasantly warm just from rising heat from the rest of the building.