Keeping the air in your home clean and safe to breathe isn’t just about having a few houseplants and living far from highly polluted areas. Without knowing, the air you breathe in your home could contain dangerous levels of radon.
Radon is a colorless, odorless, radioactive gas that can seep into your home from the ground. Long-term exposure to elevated levels of radon gas can cause lung cancer. It’s the second-leading cause of lung cancer in the U.S., after smoking, according to the Environmental Protection Agency.
Gloria Linnertz founded Citizens for Radioactive Radon Reduction, a nonprofit dedicated to radon awareness and regular testing, after her husband’s terminal lung cancer diagnosis prompted her to get her home tested for radon. “We didn’t know that we had been living with high levels of radon in our home for a long time,” she says.
The good news is that there are simple tests to tell you if your home has elevated levels of radon gas, and mitigation systems are available to lower the amount of radon in your home to less harmful levels. Here’s what you need to know about radon mitigation costs, types of radon mitigation that may suit your needs and additional steps to keep your family safe from prolonged, elevated radon exposure.
Measuring Radon Levels in Your House
Because it comes from the ground, radon is everywhere — but its concentration remains very low when mixed with the open air. Radon becomes dangerous when it’s concentrated in the living spaces of your home, where you spend the most time.
Testing for radon levels in your home has become easier over the years. You can hire a professional to conduct a test or get a do-it-yourself kit. A one-time test will determine the amount of radon — measured in picocuries per liter of air, or pCi/L — over the course of around 48 hours. EPA-approved DIY tests start around $15 through Walmart, Amazon or hardware stores. HomeAdvisor reports the average cost of a professional radon inspection is $428.
The EPA identifies 4 pCi/L as the threshold for when action should be taken to lower the concentration in your home. Radon levels fluctuate over time, and a low result from the one-time test can be reassuring, but it won’t guarantee that your home never has elevated radon levels, or that elevated levels don’t develop over time.
You also have the option to use a continuous radon monitor, which tracks radon levels over a longer period to pick up on patterns or growing concentration of radon over time. Norwegian company Airthings makes the Wave Plus, a radon and air quality monitor that measures radon gas electronically, along with other metrics, like carbon dioxide levels in your home. The radon level can then be tracked on a mobile app.
“If it goes over 4 pCi/L for a little bit, it’s not dangerous,” says Oyvind Birkenes, CEO of Airthings, based in Oslo, Norway. “What you’re looking at is if it goes over 4 pCi/L for a few weeks — then you have a problem.”
Even if you’re consistently below 4 pCi/L, you may find a radon mitigation system is needed to help reduce the threat to your family’s future health. “If the radon concentration is between 2 and 4 pCi/L, homeowners should still consider installing a radon mitigation system in order to reduce their exposure. There is no safe radon level, and concentrations below 4.0 pCi/L still pose a health risk,” wrote Kehaulani Kekoa, certification coordinator for the National Radon Safety Board, in an email.
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How Much Does Radon Mitigation Cost?
Radon mitigation typically costs between $771 and $1,179, but the cost can reach as much as $3,000 for a large home or property with multiple foundations, according to HomeAdvisor.
“The homeowner should meet with the mitigation professional and ask how much the system will cost, what maintenance is required and where it will be located,” Kekoa says. “Mitigation systems installed in a more discreet manner will ‘blend in’ better with the architecture, but will likely be more expensive.”
Only work with a professional certified in radon mitigation, and ask to see certification from either the National Radon Safety Board or the National Radon Proficiency Program. Kekoa advises independently verifying certification with either organization as well.
“If something is done incorrectly, it can do more harm than good,” Linnertz says, recalling an individual she spoke with who tested his radon level after having a mitigation system put in, only to find the radon level in his home had increased.
Types of Radon Mitigation
The type of radon mitigation system you choose may impact the total cost, and one may be considered optimal based on your home and radon level.
Active soil depressurization uses suction to pull radon gas through a pipe from the soil under the foundation of a house and out into the open air. A hole is made in the foundation and radon suction pipes are installed along with a collection chamber at the site of the hole. A fan in the pipe system then pulls the gas that seeps into the chamber up and out, where it’s expelled outside. This is the most common radon mitigation method used by professionals, and HomeAdvisor reports it ranges in cost between $700 and $3,000.
Passive depressurization creates the same hole, collection chamber and pipe system, but there is no fan to use suction to pull the radon through the pipe. HomeAdvisor reports the price range is slightly less than an active system, at $500 to $2,500.
If you have a crawl space in your home, a vapor barrier can be used to seal the underground space, with an airtight hole for the radon mitigation system to function similarly.
Repairing any cracks in your foundation and sealing your basement to better waterproof the space can also be helpful in mitigating elevated radon in your home, optimally in conjunction with a more formal radon mitigation system. HomeAdvisor reports sealing the basement is 50% less effective than other mitigation systems on its own.
What to Do After You Get a Radon Mitigation System
A functioning radon mitigation system can help protect you from exposure to elevated levels of radon gas, but it’s still important to remain diligent.
“They should test every two years even with a mitigation system, because different things can happen — different things may change,” Linnertz says.
Periodic measurements can help ensure your radon mitigation system is working properly, and check to see if nearby construction work or a subtle shift of the soil beneath your home has changed the amount of radon getting into the air you breathe inside.
“The radon level goes up and down day by day, week by week,” Birkenes says. “It’s very affected by if someone’s doing work in the ground nearby (and) it’s very affected by the weather.”
Kekoa adds that a radon test after major changes you’ve made to the house could help keep you safe. “(I)t’s a good idea to retest after any major renovations, additions or structural changes.”
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Update 10/18/22: This story was previously published at an earlier date and has been updated with new information.