Glossary · Health & indoor air
Radon mitigation (sub-slab depressurization)
Also called: radon reduction · radon remediation · active soil depressurization · sub-slab suction · radon fan · radon mitigation system
Fixing high radon, usually with a pipe through the basement floor and a fan that pulls soil gas from under the slab and vents it outside.
What it means
Sub-slab depressurization makes the pressure under the floor lower than in the house, so soil gas is drawn into the pipe instead of indoors. Sealing cracks and sumps helps but isn't enough on its own, and an HRV gives only modest reductions. The fan runs continuously, and a follow-up test confirms the fix.
Why it matters in an audit
Mitigation is usually affordable and very effective, and it's easiest to plan alongside basement air sealing or renovations.
Typical numbers
Reference values with their sources. Your energy advisor’s report gives the figure for your own house.
| What | Value | Source |
|---|---|---|
| Cost (Health Canada, 2014) | Typically $2,000–$3,000 installed, plus about $50–$75 a year for electricity | canada.ca ↗ |
| Effectiveness | Health Canada: most homes can be reduced by more than 80%; EPA: sub-slab suction cuts levels 50%–99% | epa.gov ↗ |
| Testing afterwards, Canada | Short-term test at least 24 hours after the fan starts, then a 3-month test the next fall or winter; long-term re-tests within 2 years, then every 5 years | canada.ca ↗ |
| Install time and cost (Health Canada, page modified 2026-09-22) | Usually installed in less than a day, for about the same cost as other common home repairs | canada.ca ↗ |
In Canada
Health Canada recommends hiring a professional certified under the Canadian National Radon Proficiency Program (C-NRPP) and having the follow-up long-term test done independently of the installer.