Abstract: A system, method and apparatus for transferring heat are disclosed. They make use of the first receptacle having an inlet for ingress of the first liquid, such as sewage, and an outlet for egress of the first liquid. Also provided is a second receptacle having an inlet for ingress of the second liquid, such as exhausted heated water from an air conditioning or cooling unit, and an outlet for egress of the second liquid. The second receptacle comprises a portion located in a proximity of the first receptacle. The first and second receptacles are arranged such that they allow a quantity of heat to transfer from the second liquid to the first liquid. The apparatus may be configured for inline connection to a sewerage main.