This paper analyzes the effect of rotational speed on the effectiveness of rotary-type heat exchangers. Numerical, analytical and experimental studies are carried out to investigate the influence of rotational speed, especially at low values. The governing partial differential equations for the regenerator are solved numerically with some assumptions. For a limiting case, two analytical solutions are also obtained with different assumptions. Based on the results of the numerical study and the experiments carried out using a laboratory-made rotary-type heat exchanger, an empirical equation that can be used even for very small rotational speeds is presented.