Our house is 5 years old and we have a trane furnace (80% efficiency) that is the same age. When the blower turns on (whether a/c, heat or just fan), you can hear a faint high pitched whine coming from each of the air vents (not the return vents) in the house. It starts the second the blower turns on and stops as soon as the blower turns off. The closer the vent is to the furnace, the louder the noise, e.g. our kitchen air vent is just above the furnace and it is loudest there. We've had the furnace installer out several times and they say everything is normal. But the noise is constant and annoying. The high pitched noise goes away when the furnace panels/doors are removed - particularly, the solid metal panel that covers access to the fan. The installer cut a new return vent in the metal duct that drops down next to the furnace unit in the basement (thinking we just needed to slow down the air flow in the system), but that did not correct the noise. So he left the panels off the furance and duct taped an air filter over the opening. I don't think the company really has any other solution. Any thoughts on how we can get rid of the noise and get the panels back on our furnace? Is it safe to leave the panels off and/or will it cause damage to the furnace? I'm pretty hooked on this temorary fix given that it alleviates the noise, but we can't leave it like that forever.
------------------------------------- Twin Mom