Radon is a gas that naturally occurs in some areas. Radon is suspected to be a major cause of lung cancer. When selling a home, buyers often perform a short-term radon test before signing the final contract. These tests are fairly inaccurate, and depending on the time of year, may cause a false positive result in a house that has an acceptable level of radon. It's possible to "fool" a radon detector during the winter months or rainy season, when a false positive result is likely.
Open the windows. If your basement windows are often closed, especially during wet or freezing weather, open them up before the detector is placed in your basement, if possible. This will allow some of the gas to escape.
Open the door leading from the basement to the main living area of your house. During cold and rainy weather, when the basement may be cooler than the rest of the house, radon gas can get trapped in the lowest level of your home. Opening the basement door can help some of it to rise and escape.
Request a retest if the results come back high. After a heavy rainfall or when the ground is frozen, less radon can seep out of the basement. Waiting a couple of weeks for the ground to thaw or dry can mean the difference between an acceptable test result and an unacceptably high test result.