This subcategory indexes sites put together by companies and individuals concerned with the manufacture, distribution, and servicing of heat exchanging equipment. In somewhat oversimplified terms, the intention of this equipment is to transfer heat from one surface, component, machine, or source to another, for the purpose of heating or cooling either one of them. Note: To a limited degree, some additional heat exchanger sites are included in the Furnaces_Ovens_Kilns category. Their existence is justified by the companies involved having a main focus on heat creation but a sufficiently important ancillary interest in its exchange/transfer/disposal.