Testing Procedures – The Radon Specialist

Testing Procedures

Testing procedures that must be adhered to obtain accurate results

Radon Test Device Placement

Radon Testing Unit, The Radon Specialist Greensboro, NC
EPA recommends that testing device(s) be placed in the lowest level of the home that could be used regularly, whether it is finished or unfinished. Conduct the test in any space that could be used by the buyer as a bedroom, play area, family room, den, exercise room, or workshop. Based on their client’s intended use of the space, the qualified testing professional should identify the appropriate test location and inform their client (buyer). Do not test in a closet, stairway, hallway, crawl space or in an enclosed area of high humidity or high air velocity. An enclosed area may include a kitchen, bathroom, laundry room or furnace room.

Preventing or Detecting Test Interference

There is a potential for test interference in real estate transactions. There are several ways to prevent or detect test interference:

  • Use a test device that frequently records radon or decay product levels to detect unusual swings
  • Employ a motion detector to determine whether the test device has been moved or testing conditions have changed
  • Use a proximity detector to reveal the presence of people in the room which may correlate to possible changes in radon levels during the test
  • Record the barometric pressure to identify weather conditions which may have affected the test
  • Record the temperature record to help assess whether doors and windows have been opened
  • Apply tamper-proof seals to windows to ensure closed house conditions; and Have the seller/occupant sign a non-interference agreement

Home buyers and sellers should consult a qualified radon test provider about the use of these precautions.

There are two general ways to test your home for Radon:

Because radon levels vary from day to day and season to season, a short-term test is less likely than a long-term test to tell you your year-round average radon level. However, if you need results quickly, a short-term test may be used to decide whether to fix the home.

Short-Term Testing

The quickest way to test is with short-term tests. Short-term tests remain in your home from two days to 90 days, depending on the device. There are two groups of devices which are more commonly used for short-term testing. The passive device group includes alpha track detectors, charcoal canisters, charcoal liquid scintillation detectors, and electret ion chambers. The active device group consists of different types of continuous monitors. Electret ion chambers or otherwise known in the industry as E-perms are recognized worldwide as the gold standard for accurate and reliable radon test results. READ MORE

Radon Testing Kit, The Radon Specialist, Greensboro, NCWhether you test for radon yourself or hire a state-certified tester or a privately certified tester, all radon tests should be taken for a minimum of 48 hours. A longer period of testing is required for some devices.

Long-Term Testing

Long-term tests remain in your home for more than 90 days. Alpha track, and electret ion chamber detectors are commonly used for this type of testing. A long-term test will give you a reading that is more likely to tell you your home’s year-round average radon level than a short-term test. If time permits (more than 90 days) long-term tests can be used to confirm initial short-term results. When long-term test results are 4 pCi/L or higher, EPA recommends fixing the home.

Doing a Short-Term Test

If you are testing in a real estate transaction and you need results quickly, any of the following three options for short-term Tests are acceptable in determining whether the home should be fixed. Any real estate test for radon should include steps to prevent or detect device interference with the test device.

When Choosing a Short-Term Testing Option

There are trade-offs among the short-term testing options. Two tests taken at the same time (simultaneous) would improve the precision of this radon test. One test followed by another test (sequential) would most likely give a better representation of the seasonal average. Both active and passive devices may have features which help to prevent test interference. Your state radon office can help you decide which option is best.

Short-term Testing Options

Passive Method

  • Take two short-term tests at the same time in the same location for at least 48 hours.


  • Take an initial short-term test for at least 48 hours. Immediately upon completing the first test, do a second test using an identical device in the same location as the first test.

Active Method

  • Test the home with a continuous monitor for at least 48 hours.

What to do Next?

Passive Method

Fix the home if the average of the two tests is 4 pCi/L or more.

Active Method

Fix the home if the average radon level is 4 pCi/L or more.