Discover the hidden danger in Calgary homes: radon gas. Learn about the risks, prevalence, and steps you can take to protect your family. Evict Radon campaign i
Radon is the health risk Calgary homeowners are most likely to have never tested for. It's an invisible, odourless radioactive gas that occurs naturally in prairie soils — and the only way to know whether it's in your home is to measure it. Here's what every Calgary owner, buyer, and seller should understand, without the alarmism.
What Radon Is and Why the Prairies Have It
Radon is produced by the natural breakdown of uranium in soil and rock. The glacial deposits underlying much of Western Canada left our region with soils that release more radon than many other parts of the country. The gas seeps upward and enters homes through foundation cracks, floor drains, sump pits, and gaps around service penetrations — then accumulates indoors, especially through Calgary's long heating season when windows stay closed and furnaces pull air through the house.
You can't see it, smell it, or taste it. That's exactly why testing matters: no walkthrough, inspection, or listing photo will ever reveal it.
A heated house in winter behaves like a chimney: warm air escapes near the top, pulling replacement air in at the bottom — including soil gas drawn through openings in the foundation. That's why levels tend to be highest in the lowest lived-in level, and highest in the heating season.
The Real Risk, Stated Plainly
Long-term exposure to elevated radon is recognized by Health Canada as the leading cause of lung cancer in non-smokers, and the second-leading cause overall after smoking. This isn't a fringe concern — it's why researchers at the University of Calgary launched the Evict Radon campaign to get more Alberta homes tested, and why Health Canada publishes a guideline level above which it recommends taking action.
Two things keep the risk in perspective. First, radon is a long-exposure hazard — it's about the levels you live with for years, not a reason to panic over any single reading. Second, it's highly localized: your home can test high while the house next door tests low. Age, size, and price of the home tell you very little. Neither does your neighbour's result. Only your own test does.
How to Test Your Calgary Home
Radon levels fluctuate day to day, so short tests can mislead in either direction. Health Canada recommends a long-term test of at least 91 days, ideally run through the fall and winter heating season when levels are typically at their highest and windows stay shut.
- Do-it-yourself long-term test kits are inexpensive and widely available — through the Evict Radon research program, hardware stores, and online retailers. You place the detector in the lowest lived-in level of the home, leave it for the test period, and mail it to a lab.
- Certified radon professionals (look for C-NRPP certification — the Canadian National Radon Proficiency Program) can perform measurements and interpret results, which is especially useful if a real estate timeline is involved.
What Testing Actually Looks Like, Step by Step
If you've never done it, the process is simpler than most homeowners expect:
- Order the kit in early fall. Starting in October or November lets the test run through the heating season, giving the most meaningful result.
- Choose the location. The detector goes in the lowest level where people spend real time — a basement family room or bedroom, not a crawl space — away from doors, drafts, and bathroom humidity.
- Place it and forget it. It's a small passive device — no power, no noise. Set it at roughly breathing height, note the start date, and live normally; the point is to measure the air you actually breathe.
- Wait out the full window — at least 91 days. The long window is what averages out the day-to-day swings that make short tests unreliable.
- Mail it in and read the report. Record the end date, send the detector to the lab, and you'll receive your home's long-term average and how it compares to Health Canada's guideline.
Making Sense of Your Result
What you do next depends on where your number lands relative to Health Canada's guideline:
- Below the guideline: file the report and relax. No action is recommended. Keep the document — it's useful the day you sell — and retest after any major renovation or basement development, since those change how air moves through the house.
- Near the guideline: judgment territory. Some households retest to confirm; others — particularly with a basement bedroom or decades of ownership ahead — mitigate, since exposure is cumulative and the fix is permanent.
- Above the guideline: plan mitigation with a certified professional. Not an emergency — this is a long-exposure hazard — but a project to schedule deliberately rather than defer indefinitely. The higher the reading, the sooner Health Canada recommends acting.
If Your Levels Come Back High
The good news: radon is a fixable problem. The standard remedy is an active sub-slab depressurization system — essentially a sealed pipe and fan that collects the gas from beneath your basement floor and vents it harmlessly outside before it can enter the home. Installed by a certified mitigation professional, these systems routinely bring elevated homes well below the guideline. Alberta's building code has also evolved to include radon rough-in provisions in new construction, which makes adding a full system to a newer home simpler. Sealing foundation cracks and sump openings helps, but on its own it rarely solves a genuinely elevated reading — testing again after any mitigation work is the only way to confirm success.
Installation is typically a one-day job, and the finished system is unobtrusive: a pipe from below the slab to an exterior vent, a small continuously running fan, and a gauge that shows the system is working. Insist on the follow-up test after installation — it's the proof, and it's the document a future buyer will want to see.
What This Means When Buying or Selling
Because a proper test takes three months, radon doesn't fit inside a typical condition period — which is why we encourage owners to test before a home is ever on the market. For sellers, a documented safe reading, or a professionally installed mitigation system with a post-installation test, is a genuine asset when selling your home: it removes an unknown for cautious buyers. For buyers, it's a fair question to ask of any listing, and a sensible first project in any home you purchase — our home buyer FAQ covers where it fits alongside inspections and other due diligence.
In practice: a seller who tested two winters ago hands buyers the lab report with the listing documents — question answered before it's asked. A buyer with no radon history on their new home starts a long-term test the first fall. The only bad version is the one where nobody ever tests.
The Bottom Line
Every Calgary home should be tested once — properly, over the long term — and retested after major renovations, basement development, or mitigation work. The test is cheap, the fix is well established, and the peace of mind is permanent. If you'd like a referral to a certified radon professional, or want to talk through how testing and mitigation fit into a purchase or a sale you're planning, we're glad to help.
Frequently Asked Questions
Is radon really a problem in Calgary?
The prairie soils beneath much of Western Canada release more radon than many other regions — it's why the University of Calgary's Evict Radon campaign focuses on Alberta homes. But radon is highly localized: geology tells you testing is worthwhile; only your own home's test tells you whether you have a problem.
Do new homes need to be tested too?
Yes. Age, size, and price tell you very little about a home's radon level — new homes can test high and old homes can test low. Alberta's building code now includes radon rough-in provisions in new construction, but a rough-in makes mitigation easier to add; it isn't a test result, and it doesn't replace one.
Can I just use a short-term test to save time?
Radon levels swing day to day, so short tests can mislead in either direction — reassuring you falsely or alarming you unnecessarily. Health Canada recommends a long-term test of at least 91 days, ideally through the heating season, because the long average is what actually reflects your exposure.
What if I'm buying a home and there's no time for a 91-day test?
This is exactly why radon doesn't fit inside a typical condition period. Ask the seller whether the home has been tested or mitigated and request the documentation; if none exists, run your own long-term test the first fall after possession. Months waiting for a proper result is not the risk — years of never testing is.
Does a radon mitigation system hurt resale value?
In our experience it's the opposite. A professionally installed system with a documented post-installation test answers the radon question permanently — tested, addressed, verified. That's an asset to cautious buyers, not a red flag.
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