Can You Open Windows During a Radon Test?

For a short-term radon test, homeowners generally should not open windows to ventilate the home. Proper closed-house conditions are important because unusual ventilation can change indoor radon levels during the measurement period.

What Are Closed-House Conditions?

EPA guidance for short-term tests lasting less than four days says windows and exterior doors should be kept closed, except for normal entry and exit. Windows and outside doors should be closed at least 12 hours before the test begins and remain closed during the test.

Can I Use the Front Door?

Yes. Normal entry and exit are allowed. The goal is not to seal the house completely; it is to avoid unusual ventilation that could affect the measurement.

What About Exhaust Fans?

Follow the specific instructions provided for your test. Fans or systems that bring large amounts of outside air into the home can affect test conditions. Normal operation of systems that are part of ordinary home use may be treated differently depending on the testing protocol.

What About Severe Weather?

EPA guidance says short-term tests lasting less than four days should not be conducted during severe storms or periods of unusually high winds.

Why Following the Rules Matters

A radon test is meant to produce a useful measurement of the home's indoor conditions. Opening windows, moving the device, or intentionally changing ventilation can make the result less representative.

EPA Source

EPA Home Buyer's and Seller's Guide to Radon

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General educational information only. For current federal guidance, see the U.S. EPA radon resources linked on this page.