How radon mitigation works and what it costs: common questions

It can take less than a day.

Health Canada states that a radon mitigation system can be installed in less than a day. It says that in most homes, the system will reduce the radon level by more than 80%. The actual time depends on your building and the kind of system it needs.

See how radon mitigation works

Health Canada's Radon Reduction Guide puts it at about $2,000 to $3,000 for sub-slab or sub-membrane depressurization.

That range includes material and labour. The fan then costs roughly $50 to $75 a year in electricity, depending on fan size and local rates. Fans last five to ten years or more, and a replacement runs $200 to $300.

Sealing entry routes on its own varies widely, from a few hundred dollars to $2,000 or more, and it takes a lot of labour. Health Canada does not treat sealing as a standalone solution.

These figures come from the guide's February 2023 edition. Treat them as a reference range, not a current quote.

See what radon mitigation costs and what changes the price

Usually, but not always.

Health Canada states that in most situations, a final level below 200 Bq/m³ is readily achievable with standard radon reduction methods. In a very small number of cases, the level may stay above 200 Bq/m³ despite all reasonable corrective action. Those are handled case by case. Health Canada's goal is to get radon as low as reasonably practicable.

See how radon mitigation works

A properly designed system gives long-term reduction if it keeps running and is maintained.

Health Canada's Radon Reduction Guide says the fan must run all the time. Fans last five to ten years or more and then need replacing. Check the manometer now and then to confirm it is still pulling.

Health Canada recommends a short-term test by a C-NRPP certified professional at least 24 hours after the system starts. A long-term three-month test the next fall or winter then checks that the annual average is below the guideline. Health Canada says the installer should not do the verification test, to avoid a conflict of interest. If you have an active soil depressurization system, retest every five years after that.

See how to read the labels on a radon system

It means C-NRPP has certified the person for radon measurement or mitigation work.

C-NRPP is the Canadian National Radon Proficiency Program, which certifies radon measurement and mitigation professionals. Certification is voluntary: Health Canada notes that no province or territory requires radon professionals to be certified.

According to C-NRPP, certified professionals complete required courses and exams and work to the CAN/CGSB radon standards. They must earn continuing education credits to renew every two years. Health Canada recommends hiring a C-NRPP certified professional to reduce radon, because the work requires specific technical knowledge and skill.

See what each C-NRPP certification allows and how it is earned

Use the C-NRPP certification check tool. A company showing the C-NRPP logo is not the same as a certified person who holds current certification.

Before hiring, Health Canada suggests asking how many homes the contractor has worked on and whether any were like yours. Ask for proof of C-NRPP certification. Ask whether they inspected the structure before quoting, and whether they will guarantee reducing the level to a stated maximum.

Get more than one estimate, and get each one in writing. A very low quote is worth a question, because it can mean the contractor has misjudged the job.

See how to check and hire a radon professional