Winter in Iowa means colder temperatures, closed windows, and more time spent indoors. While homeowners take steps to keep their houses warm and comfortable, there is another indoor air concern worth considering: radon.
Radon is a naturally occurring radioactive gas that can enter homes through foundations, cracks, and other openings in contact with the soil. Because homes are typically sealed more tightly during colder months, radon can accumulate indoors and reach elevated levels.
Iowa homeowners should pay particular attention to radon because the state has a significant radon problem. According to the Iowa Department of Health and Human Services, an estimated 71.6% of Iowa homes have radon levels above the EPA’s recommended action level of 4.0 picocuries per liter (pCi/L).
Winter is an especially good time to test your home because closed-house conditions can make elevated radon levels easier to identify. Here’s what you should know about seasonal radon risks, winter testing, and protecting your home.
What Is Radon and How Does It Enter Your Home?
Radon is a colorless, odorless, and tasteless radioactive gas produced by the natural breakdown of uranium in soil and rock. As it moves through the ground, radon can enter buildings through openings in the foundation.
Common entry points include:
- Cracks in basement floors and foundation walls
- Gaps around plumbing, utility lines, and pipes
- Floor drains and sump pits
- Crawl spaces and other openings between the home and soil
Once radon enters a home, it can accumulate indoors. Because you cannot see or smell it, testing is the only reliable way to determine whether your home’s radon levels are elevated.
Long-term exposure to elevated radon levels increases the risk of developing lung cancer. In fact, radon is a leading cause of lung cancer in the US, particularly among people who have never smoked.
Why Can Radon Levels Increase During Winter?
Radon can be a concern throughout the year, but indoor levels may be higher during winter. Several seasonal conditions can contribute to this increase.
Closed windows and doors
During colder months, homeowners keep windows and exterior doors closed to retain heat. This reduces the exchange of indoor and outdoor air, allowing radon to accumulate inside the home.
Changes in indoor and outdoor air pressure
The temperature difference between indoor and outdoor air can contribute to pressure differences within a home. Heating systems and the natural movement of warm air can create a stack effect, drawing soil gases into the lower levels of the house through foundation openings.
Less natural ventilation
Homeowners generally open windows less frequently during winter. With less fresh air entering the home, radon that has already entered may remain indoors and accumulate.
Frozen ground and winter soil conditions
Radon originates in the soil beneath and around your home. Winter weather can affect how gases move through the ground, while differences in pressure between the soil and your home can influence how radon enters the building.
These factors do not mean every home will have higher radon levels in winter. Radon concentrations can fluctuate depending on weather, building conditions, ventilation, and other factors. The only way to know your home’s actual radon level is to test.
Why Winter Is a Good Time to Test Your Home for Radon
You don’t have to wait until winter to test for radon. Testing can be performed throughout the year, but colder months provide a good opportunity to evaluate your home’s indoor air quality.
During winter, homes are typically kept closed to maintain comfortable indoor temperatures. These conditions can make it easier for radon to accumulate, helping identify potential problems.
Winter is also a practical time to address radon concerns before spending more time indoors during the colder months.
Consider scheduling a radon test if:
- You have never tested your home for radon.
- Your last radon test was several years ago.
- You recently completed renovations or made changes to your home’s foundation.
- You are buying or selling a home.
- You have concerns about radon levels in your basement or lower living areas.
The Iowa Department of Health and Human Services recommends testing every two years or after renovating your home. Even if your neighbors have tested their homes, their results cannot tell you what is happening in yours. Radon levels can vary significantly between neighboring properties.
DIY Radon Test Kits vs. Professional Radon Testing
Homeowners have two primary options when testing for radon: do-it-yourself test kits and professional radon testing.
DIY Radon Test Kits
Radon test kits are available through hardware stores, home improvement retailers, and other testing providers. They offer a convenient way to check your home’s radon levels without scheduling a professional appointment.
When using a DIY kit, follow the manufacturer’s instructions carefully. Proper placement, testing duration, and building conditions all matter when collecting accurate results. Depending on the type of test, the device may need to be sent to a laboratory for analysis.
Professional Radon Testing
Professional radon testing is another option for homeowners who want assistance with the testing process. A qualified radon measurement professional can perform the test according to established testing protocols and help explain the results.
Professional testing can be particularly useful when buying or selling a home, evaluating a potential radon problem, or determining whether additional testing is needed.
AmeriServ Radon Mitigation of Iowa provides radon testing services to help homeowners identify elevated radon levels and understand their next steps.
What Should You Do If Your Radon Test Results Are High?
After completing a radon test, you will receive a measurement in picocuries per liter (pCi/L).
The EPA recommends taking action when radon levels reach or exceed 4.0 pCi/L. However, radon exposure can still present a health risk at lower concentrations, so homeowners may want to consider reducing levels even when results are below the action level.
If your results indicate elevated radon, follow-up testing may be recommended to confirm the readings and determine the appropriate next steps.
If elevated levels are confirmed, a radon mitigation system can help reduce the amount of radon entering and accumulating inside your home.
How Does a Radon Mitigation System Work?
Most residential radon mitigation systems use a process called active soil depressurization.
A mitigation contractor installs a suction point beneath the home’s foundation and connects it to PVC piping that extends outside the building. A fan creates suction beneath the foundation, drawing radon gas from the soil and directing it safely above the roofline, where it can disperse into the outdoor air.
A properly designed and installed system can significantly reduce indoor radon concentrations. Post-installation testing is important to verify that the system is working as intended.
Protect Your Iowa Home from Winter Radon Risks
Radon is a year-round concern for Iowa homeowners, but winter is an excellent reminder to check your home’s indoor air quality. With windows and doors closed for much of the season, radon can accumulate without any visible warning signs.
The good news is that testing is straightforward, and elevated radon levels can be addressed with a properly installed mitigation system.
AmeriServ Radon Mitigation of Iowa provides professional radon testing and mitigation services to help homeowners identify radon concerns and reduce elevated levels. If you haven’t tested your home recently, now is a good time to get started.
Contact AmeriServ Radon Mitigation of Iowa to schedule a radon test and learn more about protecting your home and family.
Note: This article was originally published on Oct. 15, 2015 and updated on Nov. 6, 2026.