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Testing for Radon in Closed-House Conditions in Naperville, IL

To be in compliance with the Illinois state standards of practice for radon testing during a real estate transactions, a radon test must be completed within a set testing protocol to have the best and most accurate readings.


White Glove has set the following as our standards of practice for our quality assurance to be in compliance with IEMA testing law.


Bruce Fisher #RNI91155 oversees the quality assurance of all of White Glove Building Inspections, Inc. radon testing.  

Radon Tersting White Glove Building Inspections

Homeowner/Occupant Radon Testing
& Closed House Conditions

In order for a short-term radon test to be valid, the Illinois Emergency Management Agency (IEMA) requires closed-house conditions to be maintained 12 hours before the test, during the testing period (minimum of 48 hrs.), and until the monitor(s)/testing equipment is retrieved by an authorized radon technician.  


A summary of the State of Illinois Closed House Conditions are as follows:

  • All external doors and windows must be kept closed.

  • Doors may be opened only for the time required for normal entering and exiting.

  • Mechanical Systems that draws air out of the home may adversely affect the measurement results and are not to be operated and their inlet closed.   (i.e., range hoods, bathroom fans, clothes dryers, window air conditioners or whole house fans)

  • Permanently installed HVAC systems shall continue to operate.

  • Window fans shall be removed or sealed.

  • Fireplaces and wood-burning stoves must not be used and their damper must be closed.

  • Unoccupied homes shall be tested with the HVAC system set and operating throughout the measurement period in the normal range, such as 72 degrees F plus or minus 4 degrees F.

  • If at any time during the testing period winds exceed 30 miles per hour, the monitor will require an extended stay within the home.


Open windows and the use of equipment mentioned above may increase the negative pressure in the dwelling, which can raise the radon concentration and present a false positive.  Controls will be in place during the test and the test results may be ruled invalid if these closed-house conditions are not adhered to.  The monitor(s)/testing equipment may be required to stay in the home an additional 48 hours, for a total of 96 hours, per IEMA if the closed house conditions are not followed up to a full void of the test and the equipment being reset.

During the duration of the closed house condition and the radon test the homeowner/occupant should not interfere with the test in any way.  That includes but is not limited to, touching, tampering, changing location(s), turning the monitor(s) off.  To tamper with the test is against the law and may result in criminal prosecution and/or fines. IEMA has significant penalties for non-compliance with the above conditions.

White Glove is are required by Illinois State Law to explain closed-house conditions to a designated representative and/or resident prior to a radon test.  If the measurement is being made for real estate purposes, a signature from the homeowner/occupant is needed on the Homeowner/Occupant Radon Testing Acceptance of Closed House Conditions document.

Download the Agreement

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