Testing for radon in summer open windows make a low that will not last
Health Canada writes that a measurement in hot weather, in a house without air conditioning, is very likely to mislead: the windows open. Radon dilutes. The report comes back low. The next winter, house closed, the same basement can exceed 200 Bq/m³.
A longer duration reduces the problem. It does not erase it. A 91-day test started in June mixes open weeks and, if it ends in September, still little heating. The useful window remains October to April.
When summer is still the question
A cottage occupied only in July is measured during that occupancy, not in January in an empty, freezing house. Cottage. For a house lived in year-round: the season.
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.
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