When should a radon test be retested within five years?

A radon test should be retested within five years when a new addition is added to a home. This is because any structural changes to a building, such as additions or significant renovations, can affect the indoor air pressure and the pathways through which radon gas enters. These modifications can potentially alter the radon concentration levels within the home, making it essential to conduct a retest to ensure the safety of the indoor environment.

In contrast, changing paint colors, rearranging furniture, or performing annual maintenance on heating systems typically does not influence the radon levels substantially. These activities are unlikely to create new entry points for radon or significantly affect air pressure changes within the home. Therefore, they do not necessitate retesting for radon levels as these changes won't have a material impact on the radon concentrations.