The work is devoted to the development of a smart lighting system that is able to change correlated colour temperature and consists of tunable 4-components RGBW clusters controlled via three channels. It is shown that fixing a ratio between the intensities of white and red LEDs at a level of 100:9 enables obtaining high values of colour rendering in a wide range of correlated colour temperatures. The control of 3 from 4 channels simplifies the system. The influence of the red LED on CRI and luminous efficiency is analysed.