Is a short-term radon test useful when buying in Orleans?

Health Canada is clear on this: short-term measurements are not appropriate for informing mitigation decisions, and the minimum test length for a valid estimate is 91 days, with those days falling during the heating season. So a short-term test cannot give you a reliable answer for a purchase decision.

That 91-day minimum matters a great deal in a purchase. A test started during a condition period will not finish inside it unless the condition runs longer than three months. Health Canada also notes that results can vary by up to plus or minus 25% even with a proper long-term test, which is another reason a quick reading cannot serve as a pass or fail for a purchase decision.

What you can do instead is place a long-term test device, from the C-NRPP list, in a normal occupancy area of the lowest lived-in level of the home, a space someone spends more than 4 hours a day in, and let it run for at least 91 days after you take possession. Ottawa Public Health notes that radon levels vary a great deal across Canada and within the City of Ottawa, making it difficult to predict radon levels in any one home. Do-it-yourself long-term kits cost roughly $29 to $170. Health Canada recommends every home be tested, and says to take corrective action within one year if the average annual level exceeds 200 Bq/m³.

Radon testing is a separate matter from a home inspection. If you want a professionally conducted long-term test, ottawaabatement.com lists that service.

Whether radon belongs in your offer at all is a question for your agent or lawyer.