radon fan noise 13

https://radonfanreplacementreport.nexorafield.com/posts/signs-your-radon-mitigation-system-needs-a-fan-replacement

The radon fan noise is a low, consistent hum that fades into the background, sometimes with a slight vibration through the floor. It's not loud enough to disrupt sleep or conversation, but in a quiet room, it can be a steady reminder that the system is working. You might notice it more when you're listening for it, but otherwise it just becomes part of the house's ambient sound, like a fridge or furnace.