I'm trying to perform a home radon test, the first step in the instructions for the Pro-Lab Radon Gas Detector Kit read that I need to close all the windows and doors for 12 hours before hand.

Do I need to close the windows and doors in the entire house when doing a radon test, or just the ones in the basement and the door to the basement?

Also the door to the garage that leads to the basement doesn't close (no steps everything is on the same level). But I can keep the garage door closed, will this effect the result?

  • 2
    As an aside, doesn't code require a sealed door between the garage and living space? – DJohnM Aug 6 '14 at 18:04
  • Even if code doesn't require it (I'm pretty sure it does), it's a significant safety hazard, both from fumes and potential fires. And a significant energy efficiency issue, garage doors tend to leak a lot of air. – Zhentar Aug 6 '14 at 20:11
  • Nope. The only requirement for a radon test is a complete lack of logic. Once you have that you are all set to go. – Tyler Durden Aug 7 '14 at 16:19

Fresh air from outdoors is presumed to be lower in radon concentration than air that is trapped in the house. Any introduction of outside air will thus lower the radon concentration inside the house.

The answer to your exact question depends on your goal:

Are you trying to see the maximum possible concentration in your house? Then you should keep all windows and doors strictly sealed.

Are you trying to see the concentration you experience during normal life in your house? Then open windows and doors as you normally would.

Are you trying to get out of doing mitigation? Then open everything and let the fresh air circulate.

Note that radon concentration changes with, probably among other things, the height of the water table underneath the building. In my house, this results in a seasonal variation that a short-term test wouldn't catch. I determined this with a yearlong test using an electronic radon meter.

  • I'm trying to see if it's safe for me to do weight lifting in the basement or over all just trying to find out if it's safe for my family to stay in the house. We have a home test for this. Also it gets cold here and that probably means the windows will be closed alot of the time. From what I understand too it's illegal to keep people in a lease when the radon gas concentration is high in Pennsylvania, so I'd like to find out if it's safe or not. – leeand00 Aug 8 '14 at 13:20

The instructions I've seen on these are pretty clear about this, basically saying to keep windows/exterior doors closed but otherwise use the space essentially as you plan to in the future. Which makes sense..

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