The frequency fluctuations induced by the heterogeneity of renewable sources of energy require rapid growth of the producing side’s reserve capacity, which drives up the price. In this paper, modern air conditioners (ACs) are coupled with the grid to provide regulation services through frequency management. Modern ACs are inverter-based ACs, which can adjust their power consumption by changing the compressor’s operating frequency. The compressor’s operating frequency is varied as per the frequency support required from the power grid. A multi-area power system transfer function model is developed in MATLAB/Simulink. A lumped resistance–capacitance model, based on thermal-electrical analogy, is developed to simulate the frequency-sensitive behaviour of ACs. To match the power level of the regulation service of AC to the power grid, models of ACs are aggregated using normalization. A Proportional Integral (PI) controller-based strategy is developed to minimize the error between the load reference set point and grid frequency. This enables the frequency of operation to be within the limits as per the grid code. Frequency deviations are observed for single- and multi-area systems with modern ACs, where the nominal frequency is 50 Hz and the frequency deviations are observed in the range of − 0.0106 to 0.0211 Hz. Simulations show the satisfactory performance of modern ACs on single- and multi-area systems.