Why radon rises at night the house pulls on the soil
In winter, warm air leaves through the top of the house. The lower floor goes under slight suction and draws soil air in, radon included. At night, doors and windows stay shut, the heat runs, and nobody opens a window “to air the place out.” The basement level often rises in those hours, then eases a little during the day.
A continuous monitor shows that curve. The guideline of 200 compares an average, not the 3 a.m. maximum. Chasing the peak by opening a window at midnight does not change the winter. The average. Fireplace and draft.
Reference points: Health Canada, what you need to know about radon and the 200 Bq/m³ guideline. The two-year timeline between 200 and 600, and one year above 600, comes from Health Canada’s guide for radon measurements in homes.
The 4-day test gives a first reading. The 91-day test covers the three-month minimum Health Canada asks for. Both are $59 before tax: shipping, return and the laboratory are included, taxes extra. The PDF report is sent within 2 business days after the laboratory receives the detector.
Above 200 Bq/m³, mitigation is confirmed with a quote. Gaz Radon is C-NRPP certified for measurement and mitigation.
Sources
