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Can Radon Tests Be Wrong?

Friday, January 31st


Radon Testing

Radon is a dangerous naturally occurring gas that is the leading cause of lung cancer in the United States & Canada among nonsmokers. Unfortunately, this gas is odorless, colorless, and completely invisible to the naked eye, making it impossible to detect without professional help or a radon testing kit. This, of course, begs the question, can these test results be trusted?

Can radon tests be wrong?

The short answer is yes, as errors can happen with any type of test, but the likelihood of a wrong radon level reading changes greatly based on a variety of factors. Let’s break it down in greater detail. There are two main types of do-it-yourself radon tests:

Short term radon tests: This refers to a test that monitors your radon levels for 2-7 days and is the most common type of test.
Long term radon tests: This type of test monitors radon levels for at least 90 days and is less common.

Both short term and long term tests measure your radon levels, but the accuracy differs due to the length. A short term test is good at measuring your current radon levels, but these levels can fluctuate due to a number of factors, including:

  • Barometric pressure
  • Temperature/Season
  • House construction
  • Rain soaked ground
  • HVAC system
  • Improper placement of the device

This all means that it is possible for radon levels to increase or decrease after your testing period. A long term test helps to account for these fluctuations by testing your radon levels longer. In other words, short term radon tests are sufficient for most homes, but if you are really concerned about accuracy, then a long term radon test will be more reliable. The problem with long term tests is that you have to wait over 90 days for the results.

Another important note to make is that radon tests can be conducted using either radon test kits or radon testing from a professional radon contractor. While test kits are not particularly inaccurate, the results from a qualified radon contractor will always be the most accurate. A radon contractor can also help account for some of the factors that might otherwise skew the results. A licensed radon measurement professional will also ensure the radon testing device (Continuous Radon Monitor) is placed in the right location and the EPA testing protocols are followed.

What kind of errors can there be?

There are two common errors that could occur during a radon test:

  • False Positive: Your home may test higher than 4 pCi/L, but the average level over the year was actually below. While this could lead to you installing a radon mitigation system that is not strictly necessary, any level of radon is dangerous and a radon mitigation system is rarely a worthless investment, particularly considering the relatively low installation cost. This is probably the least dangerous inaccuracy as a result.
  • False Negative: This is a far more dangerous result and refers to when your home tests below the action level of 4 pCi/L, but is actually higher than that on average. This could cause you to not install a radon mitigation system when one is necessary. This is why the EPA still strongly recommends that you install a radon mitigation system if your radon levels are between 2 pCi/L and 4 pCi/L. There is no safe level of radon exposure, so taking action to reduce your levels if they are above 2 pCi/L is common.

What can you do?

The unfortunate truth is that there is no perfect system and there is always some room for inaccuracy. With that said, there are several ways to ensure you get the most reliable results possible:

  1. Work with a professional: The most important thing is to use a professional radon contractor when possible. While test kits aren’t terrible, testing by a professional is always more accurate and they will be able to account for potential interference.
  2. Use a long term test: If you are very worried about fluctuations, a long term test will give a more accurate average radon level. Although, waiting over 90 days is a lot to ask.
  3. Test a second time: If you are using a short term test kit, simply do another test. This can be done at the same time or right after the initial test. Even if you choose to have a radon mitigation system installed, this can be a good idea just to make sure the system is working as intended.

We also suggest installing a radon mitigation system if you have any radon level above 2.0 pCi/L. While the EPA may set the actionable level at 4.0 pCi/L, any level of radon is dangerous and a radon mitigation system will never be wasted. More importantly, if your home tested too low, then your family will still be safe. The last thing you want is to gamble with your health and that of your family.

As a leading network of radon professionals, we can help connect you with your local expert contractor who can perform a reliable radon test. Contact us today to find your local expert or to learn more about radon!

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