text: why can the insulating jugs can keep hot water warm?? science all materials have a heat transfer coefficient.  materials used for insulating have a much lower coefficient so the overall heat that gets transferred from one point to another over a given time is much less.  given enough time the water would be the same temperature as everything else in the system if no other heat sources are introduced.  insulators just slow down the process by making it harder for the heat to escape.