The Ductless Energy recovery units are through the wall type. The Energy recovery core is installed in a PVC pipe in the wall of your residence.
Unlike a traditional air exchanger with ducts, our devices work like our own breathing. For 70 seconds one device exhaust air from the building while another device enters air into the building. After 70 seconds each unit reverses its operation, the exhaust becomes an air intake while the other becomes an exhaust. The cycle repeats itself over and over. The quick cycle insure a optimum energy recovery and insure the recovery core nevers freezes unlike traditional ducted units.
There should be at least two devices in a building to ensure that the air pressure in the building is equal at all times.