RFU development in Europe and worldwide
Urban cold network (current situation and definition)

The first RFUs, developed for non-commercial purposes, were installed by owners of multiple buildings (hospitals, university campuses, military camps, airports), with the obvious aim of simplifying the operation of their facilities. The first commercial SFN appeared in Hartford, Connecticut (USA) in 1962.

There are an estimated 7,000 district energy networks worldwide, of which more than 1,500 are UENs. In France, in 2008, there were over 450 district heating networks (corresponding to 26,000 GWh of final energy and serving almost 2 million housing equivalents) and just 14 district cooling networks (corresponding to 894 GWh of final energy and serving 80,000 housing equivalents). RFU networks in France represent more than 130 km of pipelines, mainly in Paris, Bordeaux, Grenoble, Lyon, Monaco and Montpellier.