It was not until the early 1960s that engineers began using mineral oil as a nonpressurized heat-carrier on an industrial scale. Since that time, thermal oils have taken over around the world as the preferred heat carrier, greatly decreasing the importance of hot water. ALLWEILER has been part of this trend since "day one" and, because we built the very first "thermal oil pump", we quickly became a German industry leader in this area. Using these experiences as a foundation, ALLWEILER expanded its activities internationally in this market segment.