Short-Term vs Long-Term Radon Testing
In Central Ohio the choice usually comes down to a calendar. A purchase contract leaves room for a test measured in days, while a homeowner deciding whether to spend $1,200 to $2,400 on a system can afford to watch a whole zone 5A winter. Ohio's Radon Measurement Protocol, in the appendix to OAC 3701-69-07, defines how each kind of test is placed, run, and reported, and it builds both into its recommended order of steps.
Short-Term vs Long-Term Radon Testing
In Central Ohio the choice usually comes down to a calendar. A purchase contract leaves room for a test measured in days, while a homeowner deciding whether to spend $1,200 to $2,400 on a system can afford to watch a whole zone 5A winter. Ohio's Radon Measurement Protocol, in the appendix to OAC 3701-69-07, defines how each kind of test is placed, run, and reported, and it builds both into its recommended order of steps.
| Feature | Short-term (48 hours to 90 days) The sale test and the first screening | Long-term (more than 90 days) The year-round picture for a close call |
|---|---|---|
| Typical length | Ohio allows 48 hours to 90 days; most run 2 to 7 days | Longer than 90 days, often an entire heating season |
| Common devices | Charcoal canisters, liquid scintillation vials, electret ion chambers, continuous monitors | Alpha-track detectors and electret ion chambers |
| House conditions | Closed-building conditions starting 12 hours ahead; no run under 96 hours in severe storms or 30 mph winds | Ordinary day-to-day living |
| Home sale | The standard route: 48 hours minimum, side-by-side devices or a continuous monitor, signed noninterference agreement | Too slow for most inspection deadlines |
| Cost here | $150-$300 professional; $15-$30 kit; free Ohio kit via ohio.radon.com | Priced per device and lab; ask when scheduling |
| What it measures | A controlled snapshot of this week under closed-house conditions | The long-run average that EPA lifetime risk estimates describe |
| Role in Ohio's strategy | Always the first step; decides a sale at 4.0 or higher | An option when a first short-term result reads 4 to just under 8 |
| Best Central Ohio timing | November through March with the house closed | Place in the fall, collect after the winter |
Our recommendation
Under contract, or reacting to a first result: use a short-term test, run by an Ohio-licensed tester if money or a sale depends on it. For a borderline result in your own home, especially a summer reading between 2 and 4 pCi/L or a first result from 4 to just under 8, a long-term device set out in the fall and collected after winter gives the steadier number to decide on. Either way, test the lowest level people actually use and keep the report with the house records.
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