Hi, my name is Bob Harris. My 15 year old trane heater and my year old carrier a/c makes a loud humming noise when turned on. We get air from the vents but the noise is a nuisance. Any ideas on the problem?

Bob, Can you tell if the noise is coming from the inside or the outside unit? Do you get the noise when its heating and cooling, or just one or the other?

Hi, Jack. It's coming from inside the unit. It happens with both heat and air. Thanks

If it's coming from the inside unit and it's a humming noise it could be the transformer, blower relay or even the blower motor itself. If you turn the FAN switch to the ON position without running the AC or heat, does it still hum? If so, it's probably the blower relay or the motor. If you feel qualified, you can remove the blower cover and try to hear wear it's coming from.