The need for compact heat exchangers has led to the development of many types of surfaces that enhance the rate of heat transfer, among them the matrix heat exchangers. These heat exchangers consist of a series of perforated plates mutually separated and sealed by spacers. The goal of this research was to investigate the heat transfer process of matrix heat exchangers on the air side, at the close to ambient conditions. The research was conducted in two directions – experimental research and CFD research. The experimental investigation was carried out over a perforated plate package with the porosity of 25.6%. The air/water matrix heat exchanger was heated by hot water and was installed in an experimental chamber at which entrance was a fan with the variable flow rate and heated by hot water. The thermocouples were attached to the surface of the perforated plate at the upwind and downwind sides, as well as at the inlet and the outlet of the chamber. During each experiment, the thermocouple readings and the air and water-flow and temperatures were recorded. In the numerical part of the research, the matrix heat exchangers with different plate porosity from 10 to 50% were investigated. The results of the numerical simulations were validated against the experimental results. On the basis of the experimental and numerical results, equations for heat transfer as the function of Reynolds number and geometrical parameters was established. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 42008]