As a first look
The health unit calls a short test a snapshot, and says to follow up with a long-term kit if it shows over 200 Bq/m³ at any point. Health Canada says a short test can't settle whether you need a fix.
Short or long radon test: which one do you need?
For your own home, use a long-term test. Health Canada (opens in a new tab) says to test for at least 91 days, in the fall and winter when the heat is on. That's what we recommend too, and we don't sell short tests.
Anything under 91 days counts as a short test. Health Canada doesn't recommend tests shorter than 91 days, and says only a long test should be checked against the guideline or used to decide on a fix. The health unit (opens in a new tab) calls a short test a snapshot. (source) (opens in a new tab)
At least 91 days
How long a long-term test runs
4+ hours a day
Pick a room you spend this much time in
1 m
Minimum distance from vents, windows and doors
Why does a long test give the better number?
Radon goes up and down with the weather, the season and the time of day. A few days can catch a high or a low.
Health Canada's guideline of 200 Bq/m³ is for your average over the year, not one short reading.
When does a short test make sense?
To check a new radon system
C-NRPP (opens in a new tab) says the mitigation professional runs a short test once the fan has run at least 24 hours. A 91-day lab test after the install is included with every system we put in. Every system we put in is designed with a target of below 100 Bq/m³, well below Health Canada's guideline of 200. C-NRPP also suggests your own long-term test in the next heating season.
Buying or selling? Health Canada doesn't recommend testing during a sale. Buying or selling covers when to test instead.
What kinds of radon tests are there?
Long-term kits
You leave one out for three months or more, then mail it to a lab. Health Canada recommends two kinds: alpha-track detectors and electret ion chambers.
Short kits
You leave one out for a few days, then mail it to a lab.
Digital monitors
These show a running number. Read the 91-day average, not the daily one. Health Canada says to use one on C-NRPP's approved list (opens in a new tab) and think about replacing it after 5 years.
A certified professional
A test from a certified measurement professional, who supplies it, documents it and explains the result. Ours comes by mail and uses an alpha track detector analyzed by an independent lab. It costs $300 plus HST, with shipping both ways included. You place it, following our instructions, and mail it back. Our radon professional is C-NRPP certified for residential radon measurement and residential mitigation, and you can check that on C-NRPP's registry (opens in a new tab).
Where to get a radon test kit covers where to get each one.
Where and when should you test?
Put the test on the lowest level of your home that people use, in a room someone spends more than 4 hours a day in, like a basement family room or bedroom.
Skip the kitchen, bathroom, laundry room, storage rooms and closets. Keep the test at least 30 cm (1 ft) off the floor and at least 1 m from vents, windows and doors. Keep it away from outside walls, heat, sunlight, sump holes and electronics.
The Canadian Radon Services Index (opens in a new tab) has a detector placement tool (opens in a new tab). Pick your lowest lived-in level and a room, and it shows where in that room to put the test.
Test in the heating season, the fall and winter months when the heat is on, with at least 91 days of the test in that season.
The health unit's local study used tests of at least 91 days on the lowest lived-in level.
- 1The test, off the floor, on the lowest level you live on.
- 2At least 1 m from doors, windows and vents.
What if your short test comes back high?
Don't panic. Health Canada says to base a decision to fix on a test of at least 91 days, so follow up with a long-term test.
In the middle of a home sale? Buying or selling covers it. What is a safe radon level? explains what the number means, and My result is high covers next steps.
Book a radon test
Ready for a long-term number? See your testing options, or get a kit and test it yourself.