Radon Fan Noise Troubleshooting: Is It Normal?
A properly installed radon fan should hum quietly in the background, like a high-end bathroom exhaust fan. If you can hear it screeching, rattling, or loudly buzzing through the drywall, you have a problem.
Diagnosis 1: The High-Pitched Squeal or Metal Grinding
The Cause: Bearing failure. Radon fans run 24 hours a day, 7 days a week, 365 days a year. Over time, the sealed ball bearings inside the motor dry out, especially in extreme heat (attics) or freezing temperatures (exterior mounts).
The Fix: Replace the fan immediately.
You cannot lubricate sealed motor bearings. Once a fan starts screaming, it is drawing excess electrical current and will soon seize completely, meaning your home is no longer protected from radon gas. Check the manufacturing date sticker on the casing; most high-quality fans (like Fantech or RadonAway) have a 5-year warranty.
Diagnosis 2: Deep Rattling or Wall Vibration
The Cause: Rigid pipe mounting. If the fan was strapped tightly to a stud wall or floor joist without anti-vibration rubber isolation mounts, the motor's natural harmonic oscillation transfers directly into the home's framing. This turns your wall into a giant speaker.
The Fix: Soft-mounting the PVC pipe. An easy DIY fix is to cut the rigid plastic strapping and insert thick foam padding between the pipe and the wooden stud. The actual fan should also be connected to the PVC pipe using rubber fernco couplings, not hard-glued, to absorb vibration.
🧊 Diagnosis 3: Gurgling Water Sounds (Winter Only)
If your fan sounds like a bong or a bubbling fish tank, congratulations: your system is successfully pulling hundreds of gallons of moisture out of the earth. But the condensation is running back down the pipe, pooling above the engine impellers, and possibly freezing. The fan must be re-pitched or bypassed so water can drain back to the sub-slab pit.
How Much Does a Fan Replacement Cost?
- DIY Replacement: $150 to $250. You must order the exact same model to match the CFM (cubic feet per minute) required for your house's footprint.
- Professional Replacement: $350 to $600. A licensed electrician or mitigator will swap the fan, check the system pressure on the manometer, and sometimes run a free clearance test to ensure the vacuum seal didn't break.
Time for a Replacement?
Don't try to wire a powerful 120V fan in a cramped attic if you aren't comfortable. Find a local pro to swap your fan today.
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