Radon Levels Can Increase During Cold Weather — Here’s What Homeowners Should Know

Radon is an odorless, invisible, radioactive gas that forms naturally from the breakdown of uranium in rocks, soil, and water. Because it cannot be seen or smelled, many homeowners are unaware it may be present inside their home.

Radon enters homes through:

• Small cracks in foundations

• Gaps around pipes and utility penetrations

• Floor drains and sump pits

• Well water systems

Over time, breathing in elevated radon levels can significantly increase the risk of lung cancer. Those most vulnerable include:

• Children

• Pets

• Elderly individuals

• People with respiratory issues

• Smokers

According to the EPA, radon is responsible for approximately 21,000 lung cancer deaths in the United States each year, making it the second leading cause of lung cancer after smoking.

For smokers, the risk is even greater — exposure to radon increases the likelihood of developing lung cancer up to 10 times higher than for non-smokers exposed to the same radon levels.

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Why Radon Levels Are Often Higher in Winter

Radon levels frequently rise during colder months, especially in regions where the ground freezes.

When the soil freezes — sometimes as deep as three feet — it creates what’s known as a frost barrier. This barrier prevents gases in the soil from escaping naturally into the air.

Instead, those gases look for the path of least resistance — which often leads directly into your home.

In homes with basements, radon can:

• Build up beneath the foundation

• Enter through small cracks or openings

• Travel through pipe penetrations or sewer connections

Because gas can pass through even the smallest openings, frozen ground can actually force radon into the home, causing indoor levels to rise significantly during winter months.

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Signs Your Neighborhood May Have Radon Issues

Take a walk around your neighborhood and look at nearby homes. You may notice:

• Extra PVC pipes extending above the roofline

• A visible fan near the foundation or exterior wall

These are parts of radon mitigation systems that operate 24/7 to remove radon from beneath the home.

Some homes also have:

• A second system designed to remove radon from well water before it enters the home’s plumbing

Seeing these systems nearby is often a sign that radon is common in your area.

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Step-by-Step: How Radon Testing Works

A radon inspection is simple and non-invasive.

✅ Step 1: Schedule a Radon Test

Most licensed home inspectors offer electronic radon testing with fast, reliable results.

✅ Step 2: Test Location

All tests are conducted in the lowest livable level of the home, usually the basement.

✅ Step 3: Testing Duration

The test typically runs for 48 hours.

✅ Step 4: Winter Testing Considerations

During winter months:

• Tests are placed away from furnaces or heating vents

• Constant airflow from heating systems can interfere with results

✅ Step 5: Review Results

Results are measured in picocuries per liter (pCi/L) — the standard unit for radon exposure.

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What Radon Level Is Considered Unsafe?

The EPA recommends installing a mitigation system if radon levels are:

• 4.0 pCi/L or higher

Even homes that tested below this level at the time of purchase may now test higher — especially during winter — due to frozen soil conditions.

If your home was tested during warmer months, levels can easily increase once the ground freezes.

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Why Post-Purchase Radon Testing Matters

During highly competitive markets, many buyers in recent years waived inspections in order to secure a home. If that happened, now is an excellent time to revisit radon testing.

Even if:

• A test passed during purchase

• Inspections were waived

• The home appeared safe at the time

Conditions can change — especially seasonally.

When it comes time to sell your home, radon testing may be required again, and results may differ from earlier reports.

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Peace of Mind Starts With Prevention

We install smoke detectors and carbon monoxide alarms to protect our families — radon testing serves the same purpose.

It provides reassurance that the place you consider your safest space truly is.

As the saying goes:

An ounce of prevention is worth a pound of cure.

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Cost of Radon Mitigation Systems

Typical costs vary depending on the home and system needed:

• Air mitigation systems: approximately $2,000, depending on complexity

• Water radon systems: significantly more expensive

Water systems also require:

• Specialized filtration media

• Periodic professional disposal in a safe manner

While mitigation is an investment, it’s one that protects your health and your home’s long-term value.