Does Cold Weather Increase Radon Levels in Homes?
Radon is a silent and invisible threat lurking in many Canadian homes. At high concentrations, this odorless gas constitutes a severe health and safety risk. As temperatures drop, homeowners often ask: “Are radon levels higher in the winter?”
Understanding how radon behaves in cold weather is essential for protecting your home and family. In this article, we’ll discuss how radon levels in cold weather can increase, and what you can do to protect your home from this unseen hazard.
Why Are Radon Levels Higher in the Winter?
Radon is a radioactive gas that finds its way indoors through the smallest vulnerabilities, from cracks in the basement floor to open crawl space vents or windows. It is the second leading cause of lung cancer in Canada and is found in high concentrations in many regions across the country. But do radon levels increase in winter? The answer is yes, and the primary reason lies in how homes interact with their surroundings during colder months.
Essentially, your home’s ventilation is the biggest factor when it comes to determining indoor radon levels. Without a way to cycle the gas back out of your home, it accumulates, leading to potentially dangerous radon buildup. In the winter, homeowners are more likely to keep doors, windows, air conditioners, and other common ventilation systems closed to retain heat. This is why indoor radon levels in cold weather tend to be higher than warmer months.
The Stack Effect and Increased Radon Levels in Cold Weather
One of the key factors contributing to rising radon levels in winter is the stack effect. This phenomenon occurs when warm indoor air rises and escapes through vents, chimneys, and other openings. As warm air exits, it creates negative pressure that pulls in colder outdoor air from the ground, along with radon gas.
The stack effect is more pronounced in winter because:
- Homes are sealed tightly to conserve heat, limiting ventilation.
- Windows and doors remain closed, reducing the natural escape of radon.
- Frozen ground outside forces radon gas to take the path of least resistance—often into basements and lower levels of homes.
Do Radon Levels Increase in Winter for All Homes?
While all homes in Canada can experience seasonal fluctuations in radon levels, those with basements or crawl spaces are at greater risk. The combination of lower ventilation and increased soil gas infiltration makes these areas prime entry points for radon.
According to studies conducted by Health Canada, radon levels in cold weather can be up to twice as high as in warmer months. This means homeowners testing their homes in summer might not get an accurate representation of their year-round radon exposure.
Testing for Radon in Winter: The Best Time to Measure
Because radon levels in winter tend to be at their peak, experts recommend testing during this season for the most accurate results. Long-term radon test kits, which measure levels over a three-month period, provide a better assessment of your home’s risk than short-term tests.
If your radon levels exceed the Health Canada guideline of 200 Bq/m³, mitigation measures should be taken to reduce exposure.
Mitigating Radon in Winter
If testing confirms high radon levels, mitigation strategies should be implemented, regardless of the season. However, winter poses unique challenges due to the stack effect. Some effective radon mitigation solutions include:
- Active Soil Depressurization (ASD): A radon mitigation system that redirects radon gas before it enters the home.
- Sealing Entry Points: Cracks in basement floors and walls should be sealed to minimize radon infiltration.
- Improving Ventilation: While opening windows in winter isn’t practical, mechanical ventilation systems can help reduce radon accumulation.
Contact Groundworks for Lasting Radon Mitigation
Radon levels increase in winter, posing a serious threat to Canadian homeowners. Testing in winter provides a clearer picture of radon risks, and proper mitigation ensures safe indoor air quality year-round.
If you haven’t tested your home yet, now is the time—because when the temperatures drop, radon levels rise. If your home has a radon problem, contact Groundworks for a no-obligation radon mitigation estimate.
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