The difference between heat dissipation effect and mute performance. Toshiba central air conditioner's dual-fan external unit has stronger heat dissipation effect than single fan. Two fans working at the same time can increase the air volume and heat dissipation area, improve the heat dissipation efficiency, help the external unit run stably and prolong the service life. Outdoor units with double fans are usually quieter than those with single fans. By using two fans to work separately, the rotation speed of each fan can be reduced and the possibility of noise can be reduced.