Summary of Key Points:

  • Radon testing is the only way to know whether your home has high enough radon levels to cause a significant lung cancer risk—but short-term tests are not as reliable as long term ones.
  • Daily or hourly fluctuations in a home’s radon levels can throw off the average recorded by short term tests, whereas long term tests provide enough data to account for these discrepancies and provide precise results.
  • It may be tempting to purchase short term radon test kits because they are faster and widely available—but a radon test kit is not useful if it does not provide reliable data on the radon levels in your home.
  • It is just as easy and more or less the same price to purchase a long term (90+ days), Health Canada recommended radon test. Long term tests are available at cost from The Evict Radon National Study, and will provide you with reliable data about your home’s radon levels. Joining the study also allows you to become a citizen scientist and participate in our unbiased, third party study so we can continue learning about radon’s risks and educating the public.

Testing the radon levels in your home is the only way to know whether they are high enough to significantly increase your risk of lung cancer, but there are major differences between short term and long term testing kits—including their reliability. It’s absolutely vital that you understand these differences so you can choose the method that provides you with the most trustworthy results, and take the appropriate next steps to ensure your health is protected from radon

Below, we’ll cover the differences between short and long term radon test kits, and show you which kind is best for measuring your home’s radon levels reliably. Read on to find out why we offer long-term radon testing kits for our study and recommend them for all homeowners.

Want to know your home’s radon levels? Order a 90 day radon test kit here.

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Defining “Short Term” & “Long Term” in Radon Testing

From a homeowner’s perspective, the most noticeable difference between short and long term radon testing kits is the length of time you’ll need to leave them in your home before you can mail them back to the lab for analysis:

Long-term radon test kits monitor the radon levels in your house for at least 90 days. The Health Canada recommended testing kits we use in our national study fall into this category.

Short-term radon test kits monitor the radon levels in your home for 2-7 days. These kits are widely available online, from many hardware stores, and may even be offered by some for-profit radon professionals.

What Do Short & Long Term Radon Test Kits Have in Common?

Short and long term radon test kits both need to be placed in the home—ideally in the lowest portion of the building where people normally spend 4 or more hours per day. Once placed, the device should be left alone for the duration of the test (although picking it up briefly to dust underneath won’t hurt). When the testing process is complete, the user mails the device to a lab for analysis, according to the instructions supplied with the kit.

See Also: When and How to Test Radon Levels in Your Home

However, these apparent similarities can mislead people into believing short term and long term radon testing are equally reliable. As we’ll see in the next section, that’s not true at all.

Key Differences Between Short Term & Long Term Radon Tests


A radon test’s purpose is to tell you whether your home’s radon levels are high enough to be a significant lung cancer risk. Therefore, the reliability of a radon test is the single most important piece of criteria you should consider when purchasing one.

Via Adobe Stock.

A study conducted in 776 houses across Canada demonstrates that long term testing provides precise results in over 96% of cases—whereas short term tests fail to predict the same outcomes up to 98% of the time. This means that short term radon testing is not a viable option for getting a reliable reading on a house never tested before, and it is why The Evict Radon National Study exclusively recommends the use of long-term test kits.

The reason why short term tests fail to be as reliable is because radon levels fluctuate significantly over short periods of time, diverging by as much as 1000 Bq/m3 from the average level in a given property within a single hour. These fluctuations can throw off the average radon levels recorded during shorter testing windows, creating false negatives or positives.

As a result, homeowners may think they have a radon problem when levels are actually safe—or worse, believe their radon levels to be safe when they are actually high enough to be a lung cancer risk. Radon testing must take place over several months (ideally at least 3) to provide precise results.


Both short and long term radon test kits can be purchased from a variety of sources—but not every party selling radon test kits has the same motives. For example, we make absolutely no profit on the long term radon testing kits we sell at cost through The Evict Radon National Study. We use the de-identified data they collect to learn more about why radon poses such health risks to Canadians, guide policy decisions, and innovate ways to keep people across the nation safe from radon’s effects.

By contrast, it is possible that some people may promote the use of short term radon testing kits in order to sell mitigation systems more quickly, or to produce a rushed radon reading for a situation such as a home sale. These practices are generally not ideal, since short term radon readings can distort available information on radon levels, and lead to stigma around radon testing that can stop people from taking it seriously.

You may ask, is there ever an appropriate time for a short term radon test? The answer is—sort of. For example, if you have recently had your home mitigated for high radon, a shorter term radon test of a few weeks is considered an acceptable tool to verify that your new radon level remains as low as expected.


Both short and long term radon testing kits are relatively affordable for most Canadians. However, the perceived speed of short term tests can tempt people into purchasing them instead of more reliable long term radon tests. This is often a case of “haste makes waste” as the outcome of a short term test almost always needs to be verified by a long term test, before any action is taken, meaning people usually end up buying a long term test anyway.

Participating in our citizen science study by purchasing a long-term test kit from The Evict Radon National Study is one of the most affordable ways to procure a reliable, Health Canada recommended long term radon testing kit. Our kits are available at cost for $53.99 plus taxes, making them the same price or less expensive than most short term kits).

It’s important to remember that any perceived time saved in getting a result faster is almost never worth getting inaccurate results when it comes to radon testing. Radon exposure is the leading cause of lung cancer in Canada among people who do not smoke tobacco products, and it exponentially increases the risk of lung cancer in people who do smoke tobacco products as well—so getting reliable information about the amount of radon in your home could literally save you thousands in unnecessary radon mitigation costs or, more importantly, save you from a future lung cancer diagnosis.

What Kind of Radon Test Should You Trust?

The shorter testing period may seem like a valid reason to use a short term radon testing kit, but only long term tests provide reliable results. Given the danger radon poses to homeowners in every part of Canada, the use of long term, Health Canada recommended tests like the ones provided through The Evict Radon National Study is vital to ensure you have data you can trust about the radon risk in your home and take proper next steps by having your home mitigated for radon. Learn more about radon mitigation here, including how to find a C-NRPP certified radon mitigation professional and why that matters.

To learn more about our work, contact The Evict Radon National Study—or become a citizen scientist and participate in our work by ordering your testing kit online. Together, we can help lower radon levels and lung cancer risks in homes across Canada.