A Trane dealer installed a new a/c unit last fall. It has been working fine but I just wanted to get an independent opinion about something.
There is a constant low-level hum coming from the inside unit even when the fan is not blowing, just enough to be noticeable near the unit when the house is quiet.
I called the installer and they sent someone out who identified it as transformer hum and he ordered a new transformer. After the new part was installed, the humming noise is still there. My previous 20-year old unit was quiet in-between cycles. I Is this considered normal? Do you think it's the transformer itself or does some housing just need to be tightened?
Thanks.