My house’s radon mitigation system’s fan is getting louder. Is that a problem, and what should I do?

A louder radon fan usually means the fan motor is wearing out or starting to fail, and most radon fans last about 5 to 10 years before they need replacing. A new fan and install runs in the $900 to $6,000, and most homes land around $1,950 to $2,250 range. Don’t ignore it. A fan that quits stops protecting your home, so act while it’s just noisy and not dead.

A radon mitigation system is mostly one moving part: the fan. It runs around the clock, pulling air from under your slab and pushing it up the pipe and out above the roof. Over years of nonstop running, the motor bearings wear, and as they wear the fan gets louder. A new hum, buzz, or rattle is a motor near the end of its life.

When your fan gets louder, a few things could be happening.

Worn motor bearings, the most common cause. The fan still runs but works harder and makes more noise, and it will eventually stop.

Ice or condensation in the pipe. In a New Hampshire winter, moisture can freeze inside the pipe, especially the part running through cold attic space. The fan strains against that blockage and gets louder. If the noise comes and goes with the cold, this could be it.

Loose mounting or vibration. Sometimes the fan housing or pipe bracket loosens and the system buzzes against the wall. That one’s cheaper to fix than a new fan.

Debris in the fan. Less common, but grit or a wasp nest near the exhaust can throw the fan off balance.

How do you tell which one you’ve got? Check your u-tube manometer first, the little gauge on your pipe with colored liquid in it. If the liquid levels have shifted way off from where they normally sit, your system isn’t pulling the suction it used to, which points at a failing fan or a blockage. If the gauge looks normal but the fan is loud, you might just have a vibration or mounting issue. Either way, a loud fan is your system telling you to pay attention.

You don’t need to replace the whole system. The fan is the part that wears out, while the pipe, the seal at the slab, and the gauge usually keep going for decades. We’d rather swap a fan than sell you a new system you don’t need.

What drives the cost? A straight fan swap on an existing system is the simplest job, and that sits at the low end of $900 to $6,000, and most homes land around $1,950 to $2,250. If the failed fan was undersized or the suction was never right, we may size up the fan, and that can move the number. If your noise turns out to be ice in the pipe, the fix might be insulation or rerouting, which we price after we see it.

Here’s why a working fan matters. The EPA sets the radon action level at 4.0 pCi/L, and says to consider fixing between 2 and 4 pCi/L (source: epa.gov/radon). New Hampshire has plenty of homes that test high because of our granite bedrock, and NH DHHS tracks radon across the state. A working fan keeps your level down. A loud, failing fan is a level creeping back up.

We won’t leave you guessing on your own air, but we don’t run a post-fix retest for you. Testing your level after the work is the homeowner’s job, and short-term test kits are cheap and easy to find. If you want to know your number, run one.

Our radon work carries a 10-year warranty on the mitigation system (the radon level itself isn’t guaranteed unless we put that in writing). Branden, our radon guy we call B-Radon, has seen just about every fan failure New England throws at a basement. We self-perform this work and we’re state radon certified (RMS-113966).

If your fan is louder than it used to be, call us. We’ll come look, free, and tell you whether it’s a quick mounting fix, a winter ice issue, or a fan at the end of its road. A free inspection beats waiting until the fan dies and your radon level climbs.

Call us at 603-610-1770 or book your free inspection. We’ll give you a clear answer and a free estimate, with a quote within 24 hours.

Learn more about our radon mitigation work and what stands behind it on the 603 guarantee page.

Related questions

How long does a radon fan last? Most radon fans run about 5 to 10 years before the motor wears out. They run nonstop, so they age faster than you’d think. A fan getting loud is often the first sign it’s near the end. A replacement fan and install falls in the $900 to $6,000, and most homes land around $1,950 to $2,250 range.

What does the gauge on my radon pipe tell me? That u-tube gauge (a manometer) shows whether your system is pulling suction. The colored liquid sits at certain levels when the fan is healthy. If the levels shift way off or even out completely, your fan may be failing or your pipe may be blocked. It’s the quickest at-home check you have.

Do I need a whole new radon system if the fan is bad? Usually no. The fan is the part that wears out. The pipe, the slab seal, and the gauge typically last for decades. We’d rather swap just the fan, which keeps your cost in the $900 to $6,000, and most homes land around $1,950 to $2,250 range, than sell you a full system you don’t need.

Is radon really a concern in New Hampshire? Yes. Our granite bedrock means a lot of NH homes test high. The EPA action level is 4.0 pCi/L, and they suggest considering a fix between 2 and 4 pCi/L (source: epa.gov/radon). NH DHHS tracks radon statewide. A working fan is what keeps your home below the line.