I just got a Radon mitigation system installed and it is very loud, much louder than the AC unit that it sits next to (fan is installed outside). The housing of the fan after only a couple of hours runtime is also very hot. Not hot enough to burn when touched but hot enough that you can't keep your hand on it for very long. Is this normal? if not, what could be causing this. The contractor that installed it doesn't seem to think this is an issue, but I'm concerned of a fire risk as well how long can the fan run as hot as that before it burns out the motor? something is obviously making it work way too hard. I would love any help or feedback.

  • maybe look up the motor to see what its decibel output is at full speed. It could be bad bearings from the manufacturer. Did the contractor affirm that this is how this unit normally sounds?
    – noybman
    Jul 2, 2019 at 4:13
  • The reason I'm concerned with direct sunlight is, peak July summer sun alone will make it very hot, especially if it is a non-white color. Check it at least 2 hours after sunset. Jul 3, 2019 at 17:21

1 Answer 1


There are 2 types of Radon mitigation systems: 1) gravity, and 2) forced air.

1) Typically a gravity system will be installed, with an option to install an exhaust fan at a later date, if the gravity system is not effective.

2) After the gravity system runs for a year or so, additional readings will be taken to determine if the system is effective and has reduced the radon level. If it hasn’t, then an exhaust fan can be installed to “assist” with the mitigation (air flow) process.

It sounds like someone has determined an exhaust fan is required. First, I’d try to determine if the fan is required.

In both systems, air “intake” is required. That is to say, in order for air to flow through the pipes, there needs to be a way for air to flow into the system. So, in order for your fan to exhaust air there needs to be air allowed into the system. This intake air is called “makeup” air. (Without an intake, it’s like putting your finger over a straw that is full of water. If air can’t get into the straw, then nothing can flow out of the straw.)

Your fan could be overheating because it is unable to get “makeup” air. Did the contractors forget the makeup air intake?

  • Where are these systems common/needed? I've never seen something like this installed.
    – JPhi1618
    Jul 2, 2019 at 14:12
  • @JPhi1618 It is common in KS where we have basements for the basements to need radon systems. Nearly every home sale includes a radon test and if the average levels are above a certain threshold, radon system must be installed to complete the sale. Jul 2, 2019 at 17:32

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