Last year I stumbled across the fact that as an Austrian citizen I can get 2 Radon detectors for free. So I ordered and let them collect data - one in the bedroom, one in the basement (because that's been my office for much of COVID-19).

Today I got the results back.

Basement's ok. Bedroom's at >200% of the official limit (640Bq/m³ +/- 20Bq, limit is 300Bq/m³).

So I should probably do something about that. I just need to figure out what. The easy way of "just put in an exhaust fan in the basement" won't do since the gas doesn't seem to enter the building via the basement (only about 10-15% of the building has a basement, the rest sits directly on the ground via a foundation plate).

Guess I'll start with putting in forced ventilation (with a heat exchanger for reduced energy loss) in the living room and bedroom. At least that'd have the upside of no longer having to quarrel with the SO about airing the rooms.