Process of monitoring and/or controlling an air conditioning and/or heating plant, said plant comprising: - at least one delivery line, - at least one return line, - a predetermined number of service lines hydraulically interposed between the delivery line and the return line, each service line comprising at least one thermal exchange unit, at least one flow rate regulator configured for controlling the flow rate of the carrier fluid traversing the thermal exchange unit, and - at least one central thermal treatment group connected to the respective delivery line, wherein said process provides, for at least one of said service lines, the steps of: - circulating a carrier fluid through at least one service line so that a same carrier fluid particle traversing a first section of the service line upstream of the thermal exchange unit subsequently traverses a second section of the same service line placed downstream of the thermal exchange unit, with a hydraulic delay (dt) given by a time necessary for the same fluid particle to pass from the first to the second section, - determining at least one value of the temperature difference (ΔT) between: ▪ the temperature (T t1) of the carrier fluid, at the first section, detected at a first instant, and ▪ the temperature (T t2) of the carrier fluid, at the second section, detected at a second instant, wherein the second instant is subsequent to the first instant by said hydraulic delay (dt), - driving at least one from among: ▪ the central thermal treatment group, ▪ the flow rate regulator, ▪ a thermal exchange modulator associated with the thermal exchange unit, optionally comprising a fan, as a function of ▪ the temperature difference as measured above, or of an actual value of an operating parameter in turn being a function of the above-measured temperature difference, and ▪ a desired value of the temperature difference or of the operating parameter. - at least one delivery line, - at least one return line, - a predetermined number of service lines hydraulically interposed between the delivery line and the return line, each service line comprising at least one thermal exchange unit, at least one flow rate regulator configured for controlling the flow rate of the carrier fluid traversing the thermal exchange unit, and - at least one central thermal treatment group connected to the respective delivery line, - circulating a carrier fluid through at least one service line so that a same carrier fluid particle traversing a first section of the service line upstream of the thermal exchange unit subsequently traverses a second section of the same service line placed downstream of the thermal exchange unit, with a hydraulic delay (dt) given by a time necessary for the same fluid particle to pass from the first to the second section, - determining at least one value of the temperature difference (ΔT) between: ▪ the temperature (T t1) of the carrier fluid, at the first section, detected at a first instant, and ▪ the temperature (T t2) of the carrier fluid, at the second section, detected at a second instant, wherein the second instant is subsequent to the first instant by said hydraulic delay (dt), ▪ the temperature (T t1) of the carrier fluid, at the first section, detected at a first instant, and ▪ the temperature (T t2) of the carrier fluid, at the second section, detected at a second instant, wherein the second instant is subsequent to the first instant by said hydraulic delay (dt), - driving at least one from among: ▪ the central thermal treatment group, ▪ the flow rate regulator, ▪ a thermal exchange modulator associated with the thermal exchange unit, optionally comprising a fan, as a function of ▪ the temperature difference as measured above, or of an actual value of an operating parameter in turn being a function of the above-measured temperature difference, and ▪ a desired value of the temperature difference or of the operating parameter. ▪ the central thermal treatment group, ▪ the flow rate regulator, ▪ a thermal exchange modulator associated with the thermal exchange unit, optionally comprising a fan, ▪ the temperature difference as measured above, or of an actual value of an operating parameter in turn being a function of the above-measured temperature difference, and ▪ a desired value of the temperature difference or of the operating parameter.