Radon Levels Can Change Floor to Floor
Why Radon Levels Change From Room to Room
Daytime Radon Dips Can Be Misleading
Why Short-Term or Single-Location Tests Miss the Full Picture
As a result, two rooms in the same house can show very different radon readings at the same time. This variability is normal— and it’ s exactly why whole-home testing matters.
Radon Levels Can Change Floor to Floor
Because radon originates in the soil beneath a home, lower levels, such as basements and crawl spaces, often show higher concentrations. However, radon doesn’ t always stay confined to these areas. Air pressure differences, stack effect, and ventilation can pull radon upward into living spaces and bedrooms.
In tightly sealed or energy-efficient homes, radon can become trapped and redistributed throughout the house. This means that a low basement reading doesn’ t always guarantee safe air, especially where your family spends most of their time, especially on upper floors.
Why Radon Levels Change From Room to Room
Radon enters through cracks in foundations, sump pits, floor drains, and utility penetrations— and these entry points are rarely uniform. One room may sit directly above a radon entry point while another does not, leading to noticeably different readings.
Airflow patterns also matter. Door placement, furniture layout, and even how often a room is used can influence how radon accumulates. It’ s not uncommon for homeowners to discover higher radon levels in bedrooms, home offices, or playrooms than in nearby common areas.
Daytime Radon Dips Can Be Misleading
Many homes experience lower radon readings during the daytime. This is often caused by increased ventilation, active HVAC systems, and normal household movement that temporarily dilutes indoor radon levels.
While these daytime dips can look reassuring, they don’ t reflect long-term exposure. In many homes, radon levels rise again overnight, when windows remain closed, and air exchange slows, especially in bedrooms where people spend the most uninterrupted time.
This is why short daytime tests or quick spot checks can create a false sense of safety.
Why Short-Term or Single-Location Tests Miss the Full Picture
Traditional short-term radon tests and stationary monitors provide only a snapshot in time. While they indicate the presence of radon, they don’ t show how levels fluctuate throughout the day or how exposure changes from one room to another.