I recently moved into a new house, and it's driving me nuts—my cold air returns for the furnace are whistling all the time! We just had the furnace ducts cleaned, and the technician mentioned that the returns might be undersized, plus we don't have any returns in the basement, which he thought was causing the noise. He suggested adding a return down there could help solve the issue. Since he isn't a certified HVAC expert, I'm wondering if I should get a professional to take a look or if he's on the right track?
4 Answers
You should check to ensure that the return air filter is properly seated and not bypassing air; if that’s not it, adjusting the supply side registers or dampers might help balance out the airflow, which could be causing the noise too.
If it's whistling, it could be vibrations from the cover or ductwork. Try removing the cover and see if it changes. If it does, adding some foam tape where it screws into the duct might help quiet things down. Also, monitor how tight the grill is; I had a similar problem that was fixed just by adjusting it.
My returns were whistling too, and I had the filter changed to a lower MERV rating on my HVAC guy’s advice. It helped stop the noise. They also suggested adding an extra return to manage the airflow better. Getting a certified HVAC tech to take a look is a solid idea since there could be more going on that isn't just a quick fix.
Have you tried removing the grilles from the returns to see if the whistling stops? Also, make sure a new filter was installed after the duct cleaning; sometimes air flow can cause those sounds too. If you take out the filter and the sound goes away, that might narrow it down!
I'll definitely try removing the grilles tomorrow when I'm off work. I didn't change the filters after the clean; it was noisy before and after the clean, so I’m curious to see if I can find the source!
Totally agree! I had a similar issue and learned the hard way that airflow is crucial. Make sure to check your filter’s MERV rating and see what works best for your system.