新的HVAC噪音不大

如果return 太小，噪音会大。

SEER 跟湿气没有多少关系。If your HVAC is oversized, say you only need a 4-ton (48K BTU) machine but you installed a 6-ton machine instead, your machine will have shorter run time (more on/off cycles), meaning less time to "pump" the moisture out of your house, resulting high humidity indoor.