When it comes to radon testing, one of the most common questions we hear is: “Does it matter how long I test for?” The short answer is yes – and the difference between short-term testing and long-term radon testing can be significant. Whether you own a home in Calgary or manage a commercial property in Alberta, understanding the distinction between short-term and long-term radon testing could be one of the most important health decisions you make.
What Is Radon & Why Does Testing Matter?
Radon is a naturally occurring radioactive gas that forms from the breakdown of uranium in soil and rock. It’s invisible, odourless, and tasteless – which means you have no way of detecting it without proper testing. In Canada, radon is the leading cause of lung cancer among non-smokers.
The Health Canada guideline for radon levels is 200 Bq/m³ – any property testing above this threshold should have a mitigation system installed to reduce exposure. That said there is no “safe” level of radon, so the goal should be to maintain as low of levels as possible.
Alberta (and Calgary in particular) sits on geology that makes elevated radon levels more common than many people realize. That’s why testing isn’t just a good idea here – it’s essential.
Short-Term vs. Long-Term Radon Testing: What’s the Difference?
What’s the difference between short-term and long-term radon testing? And which is the best option for your situation?
Short-Term Radon Testing
- Typically lasts between 2 to 7 days
- Uses a rapid deployment device placed in the lowest livable area of a building
- Provides a quick snapshot of radon levels during a short time window
- Results are fast, but heavily influenced by temporary conditions
Long-Term Radon Testing
- Typically lasts 90 days or more (often through a full heating season)
- Uses an alpha track detector that continuously measures radon over an extended period of time
- Captures radon fluctuations across different weather conditions, seasons, and occupancy patterns
- Provides a much more representative picture of average radon exposure
Why Is Long-Term Radon Testing Better Than Short-Term?
Radon levels are not static. They fluctuate – sometimes dramatically – depending on a wide range of variables. A short-term test, though helpful for getting a quick snapshot of your space, captures only a brief moment in time, which may not reflect what building occupants are actually exposed to day after day.
Here are the key reasons long-term testing gives you a more accurate and reliable result:
- Radon Levels Change With the Seasons: Radon tends to be higher in colder months when buildings are sealed tighter and ventilation is reduced. A test taken in July may tell a very different story than one taken in January. Long-term radon testing averages these seasonal shifts to give you a true annual picture.
- Weather & Pressure Affect Readings: Barometric pressure, wind speed, precipitation, and temperature all influence how radon enters and accumulates in a building. A single short-term test may coincide with unusually high or low radon entry due to weather conditions that aren’t representative of the norm.
- HVAC Systems & Occupancy Patterns Matter: How a building is used, as well as how its heating and ventilation systems operate, directly impacts radon level readings. A business that runs HVAC systems 24/7 during the week, but shuts down on weekends, may see very different radon readings depending on when the test was taken. Long-term testing smooths out these daily and weekly variations.
- Building Characteristics Play a Role: In both homes and commercial buildings, factors like foundation type, soil conditions beneath the structure, and the number of entry points for radon all contribute to variability. Long-term testing captures how all of these factors interact over time – not just on one specific weekend.
When Does Short-Term Radon Testing Make Sense?
Long-term radon testing is generally the gold standard, but short-term testing isn’t without value. There are situations where a short-term test is appropriate and useful:
- Real estate transactions where results are needed quickly before a deal closes
- Initial screenings to determine whether a property warrants further investigation
- Post-mitigation verification to confirm that a newly installed radon mitigation system is working effectively
- Situations where long-term testing isn’t practical due to time constraints or property access
If a short-term test comes back elevated, the next recommended step is typically a longer-term test or immediate mitigation, especially if levels are significantly above Health Canada’s guideline.
What’s the Advantage of Radon Testing for Homeowners?
For homeowners, the benefit of long-term radon testing is to understand your potential for radon exposure – the level you and your family are breathing day in and day out, not just during one week of the year.
As a homeowner, here’s why radon testing matters for your property:
- Accurate health risk assessment: Long-term testing accounts for seasonal fluctuations, providing a much more reliable measurement of the actual levels your family breathes year round.
- Lung cancer prevention: As the leading cause of lung cancer in non-smokers, identifying elevated levels is the first step in protecting your family from long-term respiratory damage.
- Informed mitigation decisions: Having precise data allows you to install a mitigation system specifically designed for your home’s unique airflow, ensuring maximum effectiveness.
- Peace of mind: Knowing the air is as safe as possible in lower-level bedrooms, playrooms, or home offices removes the anxiety of a hidden environmental hazard.
What’s the Advantage of Radon Testing for Business Owners?
Commercial properties are just as susceptible to radon as residential ones – sometimes more so, depending on building design and how much time employees spend in lower-level spaces.
As a business owner or property manager, here’s why long-term radon testing matters for your property:
- Employee health and safety obligations: Prolonged exposure in a workplace with elevated radon levels is a real liability concern.
- Tenant and occupant trust: Demonstrating that your building has been properly tested and addressed builds confidence among tenants, customers, and employees
- Insurance and compliance considerations: As radon awareness grows in Canada, proactive testing is becoming best practice for responsible property management
Get the Full Picture With Long-Term Radon Testing
If you’re serious about understanding your potential for radon exposure, long-term radon testing is the more accurate, more reliable, and ultimately more useful option. Radon levels vary by season, weather, building use, and a dozen other factors. A short-term test can’t capture all of that. A long-term test can.
At Radon Doctors, we take a scientist-led, evidence-based approach to radon testing. We don’t guess – we measure. And we make sure you understand exactly what your results mean and what your options are, whether your levels are below the guideline or require action.
Don’t wait for a problem to become a health risk. Get your free radon test today and find out exactly what’s in the air your family or employees are breathing.