Prepare for a Professional Radon Test

For a typical short-term professional measurement, establish closed-building conditions at least 12 hours before the test begins and maintain them during the measurement period. Your provider may give different instructions when the applicable protocol or test circumstances require it.

Make the lowest appropriate living level accessible and let the provider know about crawlspaces, basement areas, HVAC zones, renovations, or other conditions that can affect placement.

Keep exterior windows closed. Use exterior doors only for normal entry and exit; do not leave doors or windows open for extended periods.

Operate heating and cooling systems normally unless the provider gives a different instruction. Do not run whole-house fans, window fans, or ventilation equipment that intentionally changes indoor air conditions. Ask your provider about unusual exhaust ventilation or fans before the test begins.

Do not move, cover, unplug, tamper with, or place objects directly beside the device. Keep children, pets, cleaners, contractors, and other occupants aware that the equipment should remain undisturbed.

If construction, an open-house event, a power interruption, a prolonged open window, or another unusual condition occurs, contact the provider promptly. Do not move or reset the device; the provider can decide whether the measurement can continue or should be repeated.

Professional testing includes placement, retrieval, result reporting, and an opportunity to ask questions about what the measurement means in context. A test result is not the same thing as a mitigation-system inspection or an installation recommendation.