An air-to-air exchanger is designed and developed based on the principle that when air is supplied to one side of a sealed room and extracted from the other, a "new air flow field" is formed indoors. It relies on mechanical air supply and extraction to forcibly create a new air flow field within the system. It is a new type of environmental-friendly electrical appliance that constantly maintains indoor air cleanliness and freshness. This independent indoor air exchange and purification system, while removing polluted air from the room, introduces fresh natural air, and first processes the incoming new air through filtration, sterilization, heating, and oxygenation.