VENCO VHR ER Energy Recovery Units are designed to provide high energy saving by using rotary type heat exchangers. The efficiency of VHR ER units is around 80% and it is higher than the efficiency of standard VHR units (aluminum plate type heat exchangers) at least 25%. Thus, the fresh air temperature gets so close to the room temperature and it would not be necessary to use any additional heaters. Rotary type heat exchangers transfer humidity as well as heat. Humidity is transferred to fresh air from exhaust air in the winter and it is transferred to exhaust air from fresh air in the summer. Thereby, the humidity level is kept close to the comfort conditions.