The present invention relates to a method for determining a set of optimized control parameters (Θk) of a closed-loop controller (3) or an open-loop controller for an HVACR (heating, ventilation, air conditioning and refrigeration) system (2). In a first method step, an outside temperature (TA), an actual room temperature (TR) of a room (9), a supply temperature (TVL), a predefined target room temperature (TR,W), and a predefined target supply temperature (TVL,W) are detected. From the detected measured values (TA, TR, TR,W, TVL, TVL,W) and a time (tk) of detection data packet (Dk) is generated, which is transmitted via an internet connection to a server (8) where the data packet (Dk) is stored in a storage medium (6, 7) connected to the server (8). In the next method step, a set of optimized control parameters (Θk) is calculated on the basis of the measured values (TA, TR, TR,W, TVL, TVL,W) of the transmitted and stored data packet (Dk) and on the basis of measured values (TA, TR, TR,W, TVL, TVL,W) of a plurality of further data packets (D0 . . . k) generated at an earlier time (t. . . k) of a specified period (Δt) and/or at least one of a plurality of previously determined sets of optimized control parameters (Θk-1) by executing a calculation algorithm on the server (8). In the following method step, the calculated set of optimized control parameters (Θk) is stored in the storage medium (6, 7) connected to the server (8) and is transmitted via the internet connection to the closed-loop controller (3) or the open-loop controller of the HVACR system (2) or to a user (B) of the HVACR system (2).