You’ve probably heard that Iowa has one of the highest average levels of radon compared to anywhere in the United States. Radon is a naturally occurring uranium element in our soil and in the water that seeps into our homes through cracks. The U.S. Environmental Protection Agency (EPA) estimates radon contributes to about 21,000 lung cancer deaths each year, mostly among people who smoke.
Sealing up houses to improve energy efficiency also traps up to 50 percent more radon inside and may lead to a higher risk of lung cancer, according to a new study described in the British Medical Journal. The study used physics models to calculate the effects of home tightening on home radon levels. Practices that reduce air exchange, such as weather-stripping along doors and windows, can cause increased levels of radon.
The study suggested that adding ventilation systems can reduce the amount of radon somewhat, and adding mechanical ventilation and heat recovery systems also reduce the amount of radon significantly.
In response to this recommendation, energy-efficient home building expert Bill McAnally, McAnally Consulting, Fort Dodge, says, “Yes, it’s true that tightening up a home may affect the radon levels. However, while this study seems to show that it traps radon inside, some other experts believe that tightening up your home may keep additional radon from entering your home. There are still unknowns about radon and the dangers.”
In any case, though, Bill says that doesn’t mean that installing a radon system isn’t a good practice. He recommends adding a radon system as a way to add basement ventilation to a home while tightening it up, and using a radon mitigation system for lower moisture levels in a basement or crawl space.
He notes that it’s possible to reduce moisture levels in a basement to “perhaps 44 to 50%”; enough that it might not be necessary to run a dehumidifier in the summer.
In his words: “Recently, an Iowan contacted me with a dilemma: She and her husband were planning to install wood floors in a living room that had a crawl space beneath it. The flooring company refused to install the wood unless there was also a ventilation system to keep the material from buckling from the moisture coming up through the ground right below. I recommended installing a radon system, which has provided the moisture control that is critical to protecting this family’s investment in their new floors.” The positive side effect in this situation, Bill adds, is that the radon levels were quite high in this home. The mitigation system brought the levels down to a reasonable level.
According to Bill, several points about radon mitigation:
- For effectiveness, your contractor should run the system out the roof of your home, not at a rim joist.
- A good contractor will make the pipe look cosmetically appealing if he/she has to take the pipe up the side of your house. It is possible to make it blend in with your home.
- Be sure your contractor tests for radon afterward (and even provides you with the test kits). You should test about every three months.
- If you need test kits, contact the American Lung Association. Kits are very reasonably priced, and the price includes the testing and receiving the results.
For more information:
- View more info. about radon from EPA
- Iowa Dept. of Public Health radon page
- Iowa certified radon mitigation specialists (scroll down the page)