The vapour microturbine set’s mathematical model has been updated to consider the partial admission of turbine stages. Experimental data from two distinct microturbine sets were used to verify the model. The model of the microturbine set was tested under varying operating conditions. Examples of a comparison between the experimental results and simulations are presented and analysed. It has been shown that, when simulating the off-design operation of multistage microturbines, not taking into account power losses due to partial admission may lead to significantly incorrect results. This conclusion does not apply to single-stage microturbines.