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Community and Q&A

Ventilation and Radon Mitigation

user-1098359 | Posted in Energy Efficiency and Durability on

Hello all-

My home is in climate zone 5a. We recently had a radon mitigation system installed due to elevated radon levels. It is a sub-slab depressurization system and is working very well.

However I have a couple of questions:

1) If I want to improve ventilation in the house (separate and apart from the radon issue), can I install an HRV or ERV or will this affect the effectiveness of the radon mitigation system? Said differently, what would be the best type of ventilation solution that would improve air quality and even help further reduce radon levels?

2) With this type of system installed, should I be wary about doing any air sealing or further insulation in the house? Will this cause radon levels to potentially rise?

3) Finally, and this is more out of general interest, is it possible to reduce the stack effect in a house (ours is 3 stories) in some simple, cost effective way?

Thanks all!


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  1. GBA Editor
    Martin Holladay | | #1

    First of all, the good news: research shows that homes like yours (with active radon mitigation systems) have much dryer basements than comparable homes without active radon mitigation systems. The radon fan is helping to keep your slab dry, and that is improving the conditions in your basement and your entire house. That's good.

    2. I have no idea how old your home is, whether it is leaky, or whether it needs a whole-house mechanical ventilation system. Many old homes don't need a whole-house mechanical ventilation system. If your windows aren't dripping with condensation, if you don't have mold on your bathroom ceiling, and if you don't have funny odors indoors, you many not need any additional ventilation.

    3. If you want to, you can certainly install an ERV or an HRV. The operation of an ERV or HRV will not cause any problems or interfere with the operation of your radon mitigation system.

    4. Performing air sealing work and adding additional insulation to your house are probably great things to do. These actions will not interfere with the operation of your radon mitigation system.

    5. The best way to reduce stack-effect air leakage is to perform air sealing work in your attic and basement. Here's a link to an article I wrote about air sealing a basement:

    There are lots of resources on this website with information on air sealing an attic; use the "search" feature. Briefly, the idea is to lift the existing insulation so you can seal any penetrations (wiring, ductwork, plumbing vents, etc.) as well as the crack between the drywall on partition walls and partition top plates. You also need to weatherstrip your attic access hatch.

  2. user-1098359 | | #2


    Thank you so much for your thoughtful answers to my questions!

    It's great to have a resource like GBA and knowledgeable, experienced people with which to converse. Sadly, I've found it difficult to find this type of knowledge amongst contractors in my area.

    So thanks again!

    I will definitely read the article you wrote on air sealing a basement.

    Thanks again.


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