The furnace is on, the windows are shut and the leaves are coming down across Central Iowa. That shift into the heating season changes more than your utility bill. It changes how much radon your home pulls in from the soil. If your home hasn’t been tested, or it’s been more than two years since your last test, this fall is a good time to book. Here’s why, and how to get on our radon testing schedule before January.
Why Radon Rises When Iowa Homes Close Up
Radon is a gas that comes from uranium breaking down in the soil. Iowa’s glacial soils carry a lot of it, and every county in the state is in EPA Radon Zone 1. Year-round, your home pulls a little soil gas in through the foundation. In the heating season, it tends to pull more.
Three things happen at once in an Iowa winter:
- The stack effect gets stronger. Warm air inside rises and leaks out near the top of the house. Replacement air gets pulled in at the bottom, and some of it comes up through the slab, the sump and gaps around pipes. The colder it is outside, the harder the pull.
- Homes stay sealed. Windows stay closed for months, so there’s less fresh air to dilute whatever radon gets in.
- Frozen ground caps the soil. When the top layer of soil freezes, soil gas has a harder time escaping into the open air. Some of it moves toward the warmer, unfrozen soil right around your basement.
The result is that many Iowa homes read higher in winter than in summer. Our guide on why radon levels change with the seasons goes into more detail.
Why fall, not January?
Testing this fall gives you a realistic heating-season number now. If it’s high, you have time to install a system before the coldest stretch of the year, instead of waiting until spring.
What Fall 2026 Testing Gets You
A realistic number
A test taken once the furnace is running and the house is closed up reflects the conditions your family lives with for the next five months. A summer test can understate your radon level. A fall test is a better look at the months that matter most.
Time to act before the coldest months
If your result is at or above the EPA action level of 4.0 pCi/L, you’ll want a mitigation system. Getting your number in October or November means you can get a price, approve it and have a system running before the deep cold of January and February. Systems work in every season, and they hold suction through the strongest stack effect of the year.
A head start on spring real estate
Iowa’s housing market picks up in spring. If you’re thinking about selling next year, testing now means no surprises during the buyer’s inspection. If you need a system, it’ll be installed, tested and documented well before you list. Buyers like seeing a system with a post-mitigation result and a 5-year warranty on file. If you’re buying in spring, keep our guide on radon testing during a home sale handy.
Your two-year retest
If you already have a mitigation system, the EPA recommends retesting at least every two years. Fall is an easy time to put it on the calendar. Not sure when you’re due? See how often to test for radon in Iowa.
January Is National Radon Action Month
Every January, the EPA and health departments across the country mark National Radon Action Month. It’s a reminder to test during the season when radon levels are often highest. Plenty of Iowa homeowners plan to test in January and then put it off as the month gets busy.
Our advice: don’t wait for January. Test in October, November or December, and if you need a system, it’ll already be running by the time Radon Action Month comes around.
How a Heating-Season Test Works
Our professional tests use a continuous radon monitor, placed on your home’s lowest livable level by an Iowa HHS-credentialed technician.
| Step | What to expect |
|---|---|
| Book | Tell us your town and any deadline |
| Close the house | Windows and outside doors shut 12 hours before and during the test |
| Placement | A technician sets the monitor on the lowest livable level |
| Test | At least 48 hours, with hourly radon readings and tamper tracking |
| Report | Your average in pCi/L, explained in plain language |
The good news about testing in the heating season: closed-house conditions are easy. Your windows are probably already shut. Your furnace can run as normal.
If Your Result Is High
A high result is common in Iowa and very fixable. Here’s the path:
- Read your number. At or above 4.0 pCi/L, the EPA recommends mitigation. Between 2.0 and 3.9, it suggests considering it.
- Send us photos. Snap pictures of your basement or crawlspace, sump, utility area and the outside of the house.
- Get a free virtual estimate. You’ll get a system design and a flat-rate price, with no visit needed.
- Book your install. Most residential installs take a single visit.
- Confirm the result. A post-mitigation test checks your new level. We routinely bring homes from above 4.0 pCi/L to below 1.0 pCi/L.
Every system and installation is backed by our 5-year warranty.
Already Have a System? A Quick Winter Checklist
- Check your manometer. Uneven liquid means the fan is pulling suction. Level liquid means call us.
- Look at the pipe outlet after a cold snap. Ice buildup at the top of exterior pipes can block the system. Our guide on winter radon pipe problems explains what to watch for.
- Listen to the fan. A steady hum is normal. Grinding or rattling isn’t.
- Keep the sump lid sealed after any pump work.
As an Iowa City radon company serving all of Central Iowa, we keep a 24/7 support line open if something looks off, whether we installed your system or another company did.
Book Before the Holidays
Fall schedules fill up as more homeowners think about winter. If you’d like a heating-season test, reach out now and tell us your town. If you already have a high result in hand, skip ahead and send us your report and a few photos for a free virtual estimate. Either way, you’ll head into January knowing your number.
Ready to test this heating season? Tell us your town to book a test, or get a free virtual estimate.