A hydrocollator, like the Hydrocollator E-1 Heating Unit - Stationary Heating Unit, is a machine that warms up and stores hydrocollator packs. The average interior temperature is between 160° F - 165° F. A temperature of 160° F is the minimum required to kill bacteria and prevent the transmission of infections from one client to the next. This is also the ideal temperature to keep hydrocollator packs before applying them to the body for treatment. The outside of the hydrocollator does get warm but it will not become as hot as the internal temperature since it is well insulated.