Аннотация:The article describes experimental and calculated data on air temperature and moisture content before and after heat exchanger, heat fluxes and energy savings during summer period of 2013 in Kiev. According to the results of experimental studies using a membrane exchanger in summer can increase the recovered heat flux due to the latent heat up to 20 % as compared with sensible heat exchanger. Calculation methods in comparison with the actual effect give more significant reduction of energy consumption due to decreasing supply air moisture content – 78.5 % (for one day), the average for the summer season – 74.6 % (using IWEC data). Average actual effectiveness ratios for summer period are 73.2 % for the sensible heat, 63.8 % for latent heat and 71.0 % for total heat.