“Radon evolution” has about 260 searches per month, difficulty 14. The site ranks around 19th place. The level in a house is not a fixed number. It rises and falls with heating, wind, and window openings.
Why Winter Has More Impact
When the house is warm and closed, it draws more air from the ground. The radon that enters stays longer in the rooms. A reading taken with windows open, or over a few hours, describes that moment. It does not describe the season.
What Is Compared to 200 Bq/m³
Health Canada intervenes above 200 Bq/m³ on a sufficiently long measurement. The 91-day test remains in place during normal life, including heating. The 4-day test detects with windows closed as much as possible. Both are priced at $74.72 taxes included: detector $39.99 + return and laboratory $25 + taxes.
Above 200 Bq/m³, the level does not “stabilize” on its own. The next step is an attenuation, at $2,799.99 + taxes for a standard installation, price confirmed before work.