Many basic home heating and cooling systems use conventional PSC motors, which are known to make a lot of noise because they always run at full speed.
What you can do:
Replace your system’s PSC motor with an energy-efficient Evergreen
ECM motor. ECM
technology runs whisper-quiet at low speed and then gradually ramps up to high speed when the thermostat turns it on.
Ask your contractor
Can my furnace noise be eliminated with an Evergreen ECM motor?