The newest edition of Caleffi’s “idronics—Circulation in Hydronic Systems” focuses on determining proper flow rates in different portions of a hydronic system. Once determined, piping and circulator selection is explored to ensure the flow rates occur when the system is built and commissioned. The journal discusses circulators and how they interact with other system components. In conclusion, a discussion of the distribution efficiency of the system and how to achieve systems that convey unsurpassed comfort using the least amount of electrical energy is examined. The journal is now available at Caleffi’s. Subscribers of the journal will receive a hard copy in February.