In this paper thermodynamical and hydraulical analysis of compact heat exchangers of different construction types has been performed in order to optimize their geometry. Thermodynamical analysis has been carried out numerically along with the evaluation of the mathematical model and corresponding numerical simulations through the experiment. In an open circuit wind tunnel developed on purpose for this investigation, the measurement of working media temperatures and mass flows for fin-and-tube and two heat exchangers with microchannel coil has been accomplished. The comparison of the obtained measurement results for the mentioned heat exchangers has been performed in relation to the heat transfer effectiveness and specific heat transfer rate per total mass and heat exchanger’s volume. For the purpose of numerical analysis and in accordance with the heat exchangers used for experiments, models with adequate geometry in direction of both air and water flow have been developed. With utilization of air/water side model, more accurate results have been achieved in relation to the model that assumes constant temperature or constant heat flux on the pipe wall. Numerical 3D models of heat exchangers have been solved using the finite volume method. The geometry optimization of compact heat exchangers has been accomplished for the heat exchanger with microchannel coil that belongs to state of the art technologies in heating, ventilating and air conditioning industry. The response surface method has been used for the heat exchanger model with four chosen parameters three of them being geometrical and one reflecting the chosen operating condition. From the thermodynamical and hydraulical point of view and based on the obtained optimization results, directions have been given for the choice of optimal geometry of the heat exchanger with microchannel coils.