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?
Best Answer
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.