How to Test Your Home for Radon
Testing for radon is straightforward and doesn't require a professional. There are two main categories: passive test kits (alpha-track detectors) and active digital monitors. The right choice depends on your goal — initial screening, long-term monitoring, or post-mitigation verification.
Long-Term vs. Short-Term Testing
Long-Term Testing (Recommended for Health Decisions)
A long-term test runs for 90 days or more. Because radon levels fluctuate daily, weekly, and seasonally, a 90-day average is the most reliable basis for health decisions and mitigation planning. This is the type of test Health Canada recommends.
Long-term tests use a passive alpha-track detector — a small sealed device that captures radon's decay products on a film strip inside. After the exposure period, you mail it to an accredited lab and receive a report with your average radon level and recommendations.
Best product: Radtrak³ Long-Term Alpha Track Test Kit — $59.95
Short-Term / Continuous Digital Monitoring
Digital radon monitors measure radon concentration electronically and update continuously. They're ideal for:
- Initial screening (results in 1–48 hours)
- Real estate transactions requiring fast turnaround
- Post-mitigation verification
- Ongoing peace of mind and seasonal monitoring
Note: short-term readings can vary significantly from day to day. Use a 7-day minimum average for screening decisions, and a 90-day average for definitive conclusions.
- Fastest results (1 hr): RadonEye RD200 — $229.99
- Battery-powered, no Wi-Fi: Airthings Corentium Home — $179.99
- Bluetooth app: Airthings Wave — $219.99
- Wi-Fi, live dashboard: Airthings View Radon — $299.99
Where to Place Your Test Device
- Lowest lived-in level of your home (e.g., finished basement family room — not an unused storage area)
- 2–7 feet (0.6–2 m) above the floor; at least 20 inches (50 cm) from walls
- Away from windows, exterior doors, drafts, vents, direct heat sources
- Not in kitchens, bathrooms, laundry rooms, or high-traffic hallways
- Passive kits: leave completely undisturbed for the full test period
How Many Tests Do You Need?
At minimum, one per regularly occupied level. A finished basement family room and main floor living room may have meaningfully different radon levels. Large homes and multi-unit buildings benefit from additional detectors placed in high-use rooms.
When to Test
- Any time of year — but heating season (October to April) tends to show higher radon due to closed windows and stronger stack effect. A heating-season test is considered conservative.
- Before buying or selling a home
- After renovations — especially if you've air-sealed, finished a basement, or changed HVAC
- After mitigation — to verify system effectiveness (wait 30–90 days post-install)
- Every 2–5 years — even in low-radon homes, periodic retesting is recommended
Understanding Your Results
Results are reported in Bq/m³ (Canada standard) or pCi/L (U.S. standard). 1 pCi/L ≈ 37 Bq/m³.
- Below 200 Bq/m³: Within Health Canada's guideline. Continue periodic monitoring.
- 200 Bq/m³ or above: Mitigation is recommended. Learn about your options →
