Homeowner Insight
You cannot see it, smell it or taste it, and the house next door tells you nothing about yours. The only way to know is a three month test, and the best time to start one is right about now.
Hello, Gorgeous! Radon is a radioactive gas that comes naturally out of the ground as uranium in soil and rock breaks down. Outside, it disperses. Inside a house, it can build up, especially in basements and in the cold months when the house is closed up.
Health Canada estimates that about 16 per cent of lung cancers in Canada are caused by radon exposure, which works out to more than 3,000 deaths a year, and it is the leading cause of lung cancer in people who have never smoked.
I am not writing this to frighten anyone. I am writing it because radon is one of the few serious home health risks that is cheap to test for and very fixable, and because a known high result is something that has to be disclosed when you sell.
What The Calgary Numbers Say
From the Cross Canada Survey of Radon Exposure, led by the University of Calgary.
| Measure | Result |
|---|---|
| Health Canada guideline | 200 Bq/m³ |
| Calgary area homes at or above 200 | 15.5 per cent |
| Calgary area homes between 100 and 199 | 36.9 per cent |
| Alberta homes at or above 200 | 16.7 per cent, about one in six |
| Newer buildings | The survey found a trend toward higher radon in newer buildings |
Source: Cross Canada Survey of Radon Exposure, 2024 report (tests from 2009 to 2024). Health Canada, Radon: What You Need To Know.
Read the second row again. About 15 per cent of Calgary area homes tested at or above the guideline, and more than a third more sat in the range just below it. Two houses on the same street can test completely differently, so a neighbour’s result is not a substitute for your own.
How To Test Properly.
Use a long term test. Health Canada recommends a test of at least three months, done in the fall or winter when windows are closed and radon levels tend to be highest.
Place it on the lowest level you spend time in. If you use your basement as a family room, bedroom or office, that is where it goes.
Get a kit or a professional. Alberta Lung points homeowners to a 90 day kit through HomeRadonTest.ca, listed in September 2026 at $70 plus GST including shipping both ways and the lab analysis. Take Action on Radon also lists Alberta kit providers. For a professional, look for someone certified through the Canadian National Radon Proficiency Program, C‑NRPP.
Start a three month test in October and you have a result by January. That is before most spring listings go live, which matters more than it sounds.
If Your Result Is High.
Health Canada’s advice is to take action to lower the level within one year if your result is above 200. The most effective and reliable method is sub slab depressurization: a pipe and fan draw the gas from beneath the foundation and vent it outside.
What it costs. Health Canada puts a typical system at about $2,000 to $3,000 including materials and labour, plus roughly $50 to $75 a year in electricity to run the fan. Take Action on Radon reports an average of about $2,700 from installs between 2013 and 2021, with more complex homes running higher. Most installs take a day.
What it does. Health Canada says a properly installed system reduces radon by more than 80 per cent in most homes.
Then test again. Health Canada recommends a follow up long term test within two years of the system being turned on, and every five years after that.
Help with the cost. The Canadian Lung Association’s Lungs Matter program offers up to $1,500 toward mitigation for eligible households, including low and moderate income households (the Alberta income threshold listed in September 2026 is $112,700). You need a long term test above 200 and a quote from a certified mitigator to apply.
“But My House Is New.”
Newer Alberta homes are built with a radon rough in: a gravel layer and poly under the slab, sealed joints, and a capped pipe ready to be connected to a fan. The Real Estate Council of Alberta says the requirement took effect in late 2015.
A rough in is not a mitigation system. It makes a system cheaper and faster to install if you need one. It does not tell you whether you need one, and the survey data above points the wrong way for anyone assuming new means low. Test anyway.
What Changes When You Buy Or Sell.
Selling. Alberta does not require you to test. But the Real Estate Council of Alberta considers a known test result above 200 a material latent defect that real estate professionals must disclose to buyers, unless a mitigation system has been installed before listing. If you test, know that a high result becomes something your agent has to disclose. If you mitigate first, you sell a house with a solved problem and the paperwork to prove it.
Buying. A proper test takes about 90 days, which is far longer than a normal condition period, so you usually cannot get a reliable result before you firm up. Ask whether the sellers have ever tested and whether there is a system. If there is no information, budget for a test after possession, and for the possibility of a mitigation system, the same way you would budget for a furnace that is getting older.
November Is Radon Action Month
Health Canada and Take Action on Radon run their awareness campaign every fall, and it is a good nudge. You do not need to wait for it. A test placed in October gives you a full winter reading.
Planning To Sell In Spring?
Radon, attic rain, an older furnace: the things a buyer’s inspector will raise are cheapest to deal with before the sign goes up. Talk to us this fall and we will help you decide what is worth doing first.
Related reading: Attic Rain In Calgary and Your September House List.
General information, current as of September 2026, and not medical, legal or building advice. Prices and programs change. Sources: Health Canada, Radon: What You Need To Know and the Radon Reduction Guide for Canadians; Cross Canada Survey of Radon Exposure (2024); Take Action on Radon; Alberta Lung; Canadian Lung Association, Lungs Matter; Real Estate Council of Alberta (2017 and 2025).
Disclaimer: This document is not intended to solicit buyers or sellers currently under contract with a brokerage.