Household heat exchangers are typically designed as a whole, with two speed controlled centrifugal fans and requiring an efficient heat exchanger core made of paper or polymer material. This can separate the moist and warm air discharged from the incoming fresh air, allowing the heat from one side to be transferred to the other and heated. At the same time, the two airflows are not mixed, allowing more than 70% of the heat to be transferred to the incoming air, which would otherwise be lost, thereby ensuring energy savings and balanced ventilation.

Assuming a heat exchanger is used in a certain area, the outdoor temperature in winter is minus 10 ℃, and due to heating reasons, the room temperature is 20 ℃. If fresh outdoor air is introduced, the temperature will be minus 10 ℃, which is 30 ℃ different from the indoor temperature. Raising such a high temperature consumes a lot of energy. If the heat from the 20 ℃ air discharged indoors can be recovered to heat fresh cold air, it can significantly reduce energy consumption. According to relevant requirements, the heat recovery rate of fresh air products needs to reach 70%. Effective heat recovery makes the fresh air system more energy-efficient.