I tested my basement for radon, and found that it was twice the allowable level (8 pCi/L). Can I use an air-to-air heat exchanger to reduce the radon level, and to pump fresh clean air into my basement and the rest of the house? How effective are these compared to conventional radon reduction systems?

My house was built in 1915, and the basement floor was repoured and the walls resurfaced a few years ago - I don't think that I can reduce the radon by sealing cracks.

In addition to reducing radon, the air-to-air heat exchanger would also reduced other pollutants that are generated inside the house - I don't understand why it isn't used more instead of conventional radon removal techniques.

2 Answers 2


You are much better off preventing it from entering in the first place. But once it does enter, ventilation is the only way to reduce the levels. How effective this would be depends on the exchange volume. You would be committed to running this exchanger 24/7 for ever. Replacement costs would be much higher than the typical radon fan. Anything running 24/7 will wear out eventually.

And there is still a significant energy loss running like that at decent volume. They are no where near 100% efficient.

If the floor was poured over a layer of gravel, a retrofit sub slab extraction system would likely be successful. If it was poured on compacted earth, a successful system is much less likely. You are right, just sealing cracks without any other remediation would not be very successful.

Testing for adequate sub slab permeability isn't too involved, drill a few well spaced holes through the slab and see if sucking air out of one hole draws air into the others.


I use an ERV. Levels started in the 8's -11'2. Now it ranges from under 1 to 2.5 or so. The issue I run into is the ERV has had severe issues about 1 x per year (3 x's now). So I am looking at other exchanger options. I'm just not thrilled about drilling holes in my foundation...

  • Could you elaborate on the "severe issues" you've had running an ERV?
    – feetwet
    May 4, 2015 at 1:02
  • Curious about the size of your house, where the HRV was placed and which unit it is...
    – Josh M.
    Oct 4, 2021 at 23:40

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