Why Winter Is Radon Testing Season in Nebraska
September 1, 2026
Radon readings run highest when the house is closed and the furnace is pulling. In Lincoln that is the heating season, which is why a winter test is the one that tells you the number you actually live with.
The stack effect in a Lincoln winter
When it is 15 degrees outside and 70 inside, warm air rises through the house and leaks out the top, and replacement air is drawn in at the bottom. Part of that replacement air comes from the soil through the slab, the floor-wall joint, the sump pit and any crawl space. That pull is the stack effect, and it is strongest in the coldest months.
The result is that the same house that reads 2.8 in June can read 5.5 in January. Neither reading is wrong; the winter one is closer to the annual exposure in the rooms people use most, because people spend more time indoors with the house closed in exactly those months.
What closed-house conditions mean
A valid short-term test requires the house to be closed for 12 hours before the test starts and for the full 48 hours or more of the test. Closed means windows and exterior doors shut except for normal coming and going, no whole-house fans, and the HVAC running as usual. In winter that is how the house is already being lived in, which is why winter tests rarely have to be thrown out.
A summer test with a window cracked overnight is not a valid test and a licensed tester will note it. Radon testing protocols are built around closed-house conditions because the number only means something if the house is behaving like a house.
- 12 hours closed before the monitor starts; 48 hours minimum during.
- Lowest lived-in level, away from drafts, exterior walls, sumps and HVAC vents.
- Normal furnace operation; no fireplace use if it draws combustion air from the room.
- No severe weather during the test; high winds and rapid pressure changes distort results.
Short-term versus long-term, and which to run when
Short-term tests, 2 to 7 days, are the tool for real estate and for a first answer. Long-term tests, 90 days to a year, average out weather and season and give the exposure figure that health guidance is built on. The ideal sequence for a Lincoln homeowner is a short-term test in winter and, if it lands between 2 and 4, a long-term test through the following year.
The 2-to-4 guide walks the middle band. A winter short-term reading under 2 usually means the house is fine year-round; a summer reading under 2 does not carry the same reassurance.
Why Lancaster County homes should test at all
Lancaster County averages 3.6 pCi/L across 19,828 state-reported tests, sits in EPA Zone 1, and shares a state where roughly 54 percent of single-family homes screen above the action level. A winter test is the cheap way to find out which side of that average a house falls on.
Test kits from the state program and local health departments work for a first read; a licensed continuous monitor is the tool when the number will be used in a transaction or to size a system.
After the reading
Under 2: retest in two years or after any major change to the house. Between 2 and 4: consider mitigation and run a long-term test. At or above 4: a licensed system, then a post-mitigation test.
For Lincoln households that have never tested, a radon reading this winter is the most useful hour of home maintenance available between now and spring.
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Quick Answers
Is a summer radon test worthless?
No, but it tends to read low. If a summer test comes back near or above 4, the house has a real problem. If it comes back low, a winter test is still worth running before concluding the house is fine.
Where in the house should the test go?
The lowest level that is lived in or could be, typically the basement if it has a finished room or is used regularly. Place it three feet off the floor, away from exterior walls, windows, sumps and vents, in a room that stays closed up.
Does a new furnace or air sealing change the reading?
It can. Tightening a house reduces the air that dilutes radon, and a new furnace or ventilation system changes house pressure. EPA recommends retesting after HVAC changes, major renovations and foundation or basement work.