A radon fan runs around the clock, so like any motor it eventually wears out. EPA says fans may last five years or more and that manufacturer warranties tend not to exceed five years. Kansas State University’s EPA-funded radon program puts typical lifespans at 10 to 15 years (EPA, Consumer’s Guide to Radon Reduction; National Radon Program Services). Replacing a fan is a routine repair, not a new system.
Signs your radon fan needs attention
- The gauge has gone level. On a U-tube manometer, the liquid sits higher on one side while the fan is pulling suction. If both sides are even, the system isn’t working (MDH).
- The alarm sounds, if your system has one.
- The fan is silent or not running. Check the breaker, the switch or the plug first.
- New noise or vibration. A radon system is supposed to be quiet. EPA’s standards require systems to be designed to minimize noise, and fans to be mounted so they pass little vibration into the house (EPA, Radon Mitigation Standards). A new rattle, hum or grinding is worth having checked.
- A follow-up test comes back high. Retest at least every two years even if everything looks normal (EPA, Consumer’s Guide).
If the gauge shows the system isn’t working, EPA says to call a contractor to check it.
Noise: what’s normal
Kansas State University’s radon program describes a radon fan as quiet and continuously operating (sosradon.org). If yours has become noisy, these are the things to have checked:
- Vibration carried into the framing. The fan should be secured to minimize it (EPA standards). A loose mount or a pipe touching a joist can carry sound through the house.
- Water in the pipe. Soil gas is humid, and the moisture condenses in the pipe. A properly installed system lets it drain back down to the ground under the slab; a badly installed one can let water pool in the pipe or freeze in unheated spaces (sosradon.org; EPA standards). Gurgling or dripping can mean the pipe isn’t sloped to drain.
- The fan itself. New grinding or squealing can mean a mechanical problem in the fan.
Never switch it off to stop the noise
The fan has to run continuously for the system to work (EPA, Consumer’s Guide). If the noise is a problem, have the installation checked rather than turning the fan off.
Replacing a radon fan
EPA’s installation standards require the fan to be connected with removable couplings so it can be serviced and replaced (EPA standards), so in most homes a replacement means unclamping the old fan and fitting a new one in the same spot. Points to check:
- Who can do it. In states that license radon mitigators, such as Pennsylvania, Minnesota, Iowa and Colorado, check with your state radon program whether the work must be done by a licensed professional. Your original installer’s warranty may also cover the fan.
- Use a fan made for radon systems, sealed against soil-gas leaks, and rated for outdoor use if it’s mounted outside (EPA standards). Keep the original size unless the installer recommends a change.
- Retest afterward to confirm radon is back down (EPA, Consumer’s Guide).
Pennsylvania’s DEP puts a replacement at about $250 to $350, parts and labor included. See radon fan replacement cost for details.