Home Buyer's and Seller's Guide to Radon is a publication by the Environmental Protection Agency. Used with permission under public domain and creative commons. Usage: Category Education; License: Creative Commons Attribution license (reuse allowed)
On this page: Active [Radon Testing] Devices
Active radon testing devices require power to function. These include continuous radon monitors and continuous working level monitors. They continuously measure and record the amount of radon or its decay products in the air. Many of these devices provide a report of this information which can reveal any unusual or abnormal swings in the radon level during the test period. A qualified tester can explain this report to you. In addition, some of these devices are specifically designed to deter and detect test interference. Some technically advanced active devices offer anti-interference features. Although these tests may cost more, they may ensure a more reliable result.
b. General Information for All DevicesA state or local radon official can explain the differences between devices and recommend the ones which are most appropriate for your needs and expected testing conditions.
Make sure to use a radon measurement device from a qualified laboratory. Certain precautions should be followed to avoid interference during the test period; see the Radon Testing Checklist for more information on how to get a reliable test result.
Radon Test Device Placement
EPA recommends that the test 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.