I just installed a DIY radon mitigation system. I went with a Festa AMG Prowler fan. The system seems to be working great. The radon lowered from around 9 average in the worst room in the basement to .3 or less average.

My question is around flow. I'm showing slightly under 3" water column on the manometer which is more than the Prowler is rated for (2.7"wg). As expected, I can feel very little flow coming out of the pipe. The fan is pulling around 70 watts when connected to the pipe and 110 watts if I remove it from the suction and let it flow free. It does feel warm to the touch, not hot by any means though. I thought about installing a bigger fan but I'm not looking to waste electricity if what's there is working well already. My concern is that I'm just going to burn up the fan.

Should I upgrade the fan or just leave it as is if it's working well?

Thanks, Rick


3 Answers 3


There isn't much radon bubbling up into the space under the foundation. It doesn't take a lot of vacuum to pull a lot of it to and through the duct. If what's installed meets the specs, trust the specs.

If still nervous, you can buy a radon test kit which comes with analysis; unseal it, hang it in the basement as directed for the time directed, seal it and send it to the lab; a week later you'll have a number and an explanation of what that number means. Note that the number will probably not be zero, but if the mitigation system is working it will be low enough not to worry about.

(Note that if you are going to put a bedroom in the basement, or otherwise have people there for unusually long times on a frequent basis, the "safe enough" level is lower than if you only spend a few hours a week in that space. What matters most is cumulative dosage over time, and less time means less risk.)


IT's not broke...don't fix it.

  • This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post. - From Review Mar 17 at 5:05
  • The question the OP has was should he upgrade or leave a fan that was still performing well. My answer gave him outside opinion. Which is what he was asking for.
    – RMDman
    Mar 17 at 12:44
  • Terse but correct, so I consider it helpful and up-voted.
    – keshlam
    Mar 17 at 12:59
  • @ keshlam, Thank You
    – RMDman
    Mar 17 at 13:03

You would not be looking for a bigger fan, if you were doing this right, from what you have reported.

You would be looking for a lower-flow, high-suction fan, at lowest possible power. That one is 221CFM/2.7" suction. At 115 watts! Yikes. Shop perhaps 150CFM (-ish) units that have high suction combined with the lower airflow.

But you're not too far off spec, so do your research so you'll know what to buy for the next fan, rather than fussing about replacing this one before it dies. They all die, it's unlikely that a 3" WC (actual) on a 2.7" (max rated) fan will kill it quickly. Different fans are optimized for high flow or high suction, and your next fan should be optimized for high suction.

It's also possible that as you run the system for a few weeks the soil flow will increase as things dry out where you're sucking on it. One reason you have manometers is that it's not going to always stay the way it was the day you turned it on.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.