Closed building conditions and air circulation. Since radon and its decay products can fluctuate from hour to hour and season to season the following recommendations for closed building conditions and air circulation were developed by the EPA to provide standardized conditions under which a short-term radon survey is to be performed in order to reduce the variation the radon levels in foresaid property. These conditions will tend to maximize the radon measurement in order to determine if a dwelling has the potential to have an elevated radon level. All exterior windows and doors must be kept closed. All doors to and from the lowest livable area must be kept closed except for normal momentary entering and exiting during testing. Heating, air conditioning, dryers, range hoods, bathroom fans and attic ventilators can be operated normally. However any heating, air conditioning or ventilating equipment that has a built in outdoor air supply that is manually controlled, shall be turned off or the inlet closed. Fireplaces or wood stoves shall not be operated unless they are a primary heat source. Whole house fans shall not be operated. Window fans shall be removed and sealed shut. These test conditions must be initiated 12 hours prior to start of the radon device being placed and must be maintained for the duration of the testing not exceeding 4 days.


  • Keep all windows closed.
  • Keep all exterior doors closed except for normal entry and exit.
  • Leave all heating or AC thermostats at normal settings.
  • Do not operate whole-house fans, fireplaces or wood stoves.
  • Do not touch or move the detectors. ┬áTampering with the detectors or refusal to follow these protocols will void the test.