Mark wrote:
As far as the sealed house having lower levels in the winter...
In a controlled, sealed environment as temp increases so does air
pressure. A warm sealed house will have higher pressure than outside
and under the slab. The radon goes elsewhere.


This is wrong. A house is not "sealed". Hint: if you open an
basement window in the winter, does cold air flow in or does hot air
flow out?

Answer: Both.


In the winter, the inside of a home is usually at a LOWER pressure
compared to outside because heated air escapes small openings near the
upper portion of the home. That is why more radon is usually drawn in
during the winter.


Huh?

Admittedly, the heated air escapes, but that doesn't lower the air pressure
in the house - it equalizes the pressure to match the outside. If it didn't
leak out, the house would explode. Or rise off the foundation.