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Community and Q&A

Most energy efficient Radon Mitigation Fan?

C L | Posted in Green Products and Materials on

Does anyone know which brand/model series of radon mitigation fans are the most energy efficient?  It is my understanding radon mitigation fans run continuously, so efficacy and silent operation would seem to be primary concerns, but I’m not finding much info about this.

Unfortunately, does not have a specific Radon Fan category.  Filtering by ventilating fans, and further by In Line single port and multi port fans, returns a list of many fans of the type typically used for radon mitigation.  But further investigation indicates not all such fans are ideal for radon. 

For example, the NuTone ILF120 has a efficacy of 6.3, pulling 0.2 amps, but the NuTone website Q&A for this model recommends the ILRF for radon. The ILRF is not Energy Star rated, nor is it rated to run continuously, and it pulls 0.7 amps.


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  1. Charlie Sullivan | | #1

    Take a look at Fantech. Here's their Radon Fan Brochure:

    The Rn1 is a low pressure fan with very low power consumption, if that's adequate. Then Rn4EC is a variable speed fan that can can be adjust to use no more power than necessary to do the job.

    Ideally, you run a test with a variable speed fan temporarily installed and with some sub-slab pressure measurements to figure out what you need in terms of flow and pressure, and then order the fan that does that job with the lowest power consumption. Alternatively, you could install a variable speed fan and monitor radon levels with different speeds to find what works.

  2. C L | | #2

    Thank you Charlie - VERY helpful.
    I've got an encapsulated crawl, with a pit, some gravel, and a pipe under the poly and a PVC pipe from the gravel pit pipe, venting up through the attic, all already installed.

    Would an HVAC sub normally install the system from this point on, or does it usually require a specialized radon mitigation sub? I could probably install the thing myself but read a manometer should also be installed, so figured I'd leave it to the pros.

    For the variable speed one, how do you usually control that? Do you play around with it until you find the lowest setting that results in an acceptably low radon reading over time, or is it connected to a sensor that automatically and/or continuously adjusts it?

  3. Charlie Sullivan | | #3

    Here's my understanding as an engineer, but not a certified radon professional:

    The old way to do it is to guess and check: to put in a fan, and then measure pressure under the slab, far from where the fan is pulling. If it's good, leave it, and if it's not, get a bigger fan. That requires drilling holes at other points in the slab to measure.

    The modern way to do it is to buy a $2000 kit from Fantech that includes a variable speed fan, a manometer, and various charts. Basically you put the manometer on the hole you drilled for measuring depressurization under the slab, as in the traditional approach, and adjust the fan until you get the prescribed reading far away under the slab. Then you measure what flow and pressure that required from the variable speed fan. You plot that point on a chart that shows the capability of all of their fans and pick out the lowest power consumption option that can do it.

    I think that kit is pretty new, and I'm not sure how easy it would be to find a pro who has the kit and knows how to use it properly. I bet most are still doing guess and check.

    In your case, the setup sounds very good--you won't be trying to suck air through old clay-filled sand under the slab--rather, you actually have a known good setup for it. So I think that you would likely have success with the lowest power Fantech fan, just installing it and skipping the sub-slab depressurization measurement, and just monitoring radon levels. If that doesn't work, you could opt to get the variable speed one and experiment with the radon readings vs. the setting, leaving it for a few weeks at each setting, or you could at that point hire a professional to either use the kit to do a proper fan selection process, or to adjust the variable fan based on measuring sub-slab depressurization.

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