This paper presents a case study of the heat recovery of air handling units with heat exchangers for residential application in Latvia. The paper will be summarizing the measurements of configuration for air handling units with air-to-air heat exchangers. The research carried out analytical studies analyzing an optimum variant of the energy savings with regard to different type of the air-to-air heat exchangers and their technical performances. The results show that basic methods of air handling unit’s optimization should be encouraged due to the potential of energy savings in Latvia’s residential area. Reduction of energy consumption, improvement of energy efficiency and optimization of air handling units for the residential area are important issues to address the improvement of indoor air quality.