The following is a little information on how to prep for and to get the most accurate results on your radon test.
Closed-house conditions must be to be maintained 12 hours prior to the test. This test period will be 48 hours + and must be made under closed-building conditions. Closed-building conditions are necessary in order to stabilize the radon and radon decay product concentrations, and increase the reproducibility of the measurement.
Windows on all levels and external doors should be kept closed (except during normal entry and exit) during the measurement period. Normal entry and exit include a brief opening and closing of a door, but — to the extent possible — external doors should not be left open for more than a few minutes.
In addition, external-internal air-exchange systems (other than a furnace and air conditioners), such as high-volume, whole-house and window fans, should not be operating. However, attic fans intended to control attic (and not whole-building temperature or humidity) should continue to operate.