The short answer
For personal peace of mind, a quality DIY kit used exactly as instructed is a reasonable first step. For a real estate transaction, post-mitigation verification, or any decision where money changes hands, use a professional continuous monitor test.
Side by side
| DIY kit | Professional test | |
|---|---|---|
| Device | Charcoal or alpha track, lab analyzed | Calibrated continuous radon monitor |
| Result | A single average value | Hourly data plus average |
| Turnaround | 3–7 days for lab results | Same day the device is retrieved |
| Tamper detection | None | Motion, tilt, and condition logging |
| Placement and protocol | Your responsibility | Handled and documented |
| Accepted in transactions | Often not | Yes |
| Cost | Low | Higher, includes two visits and a report |
Where DIY tests go wrong
- 1Closed-house conditions were not maintained for 12 hours before and during the test.
- 2A swamp cooler or window fan was running — a very common New Mexico mistake.
- 3The kit was placed in a closet, on the floor, or against an exterior wall.
- 4The kit sat out longer than its rated exposure window.
- 5It was not mailed to the lab promptly, so decay continued after the exposure period ended.
None of these are device failures. They are procedure failures, and they all push the result in unpredictable directions.
When you must use a professional
- A home purchase or sale, where the other party relies on the number.
- Verification after a mitigation system is installed or repaired.
- Diagnosing why an existing system is not performing.
- Any result you intend to present to a lender, agent, or attorney.
A sensible sequence for a homeowner
- 1Start with a short-term DIY kit under strict closed-house conditions.
- 2Below 2.0 pCi/L: retest in two years.
- 32.0 – 3.9 pCi/L: run a long-term alpha track test for your annual average.
- 44.0 pCi/L or higher: get a professional test or proceed to mitigation design.
Should I mitigate?
Guidance based on EPA action levels. Your specific situation may vary.
Mitigation recommended
You are at or above the EPA action level of 4.0 pCi/L. The EPA recommends fixing homes at this level.
Related services
Keep learning
- Radon Testing Methods ComparedEvery radon test measures the same thing, but the method determines how much you can trust the number and what decisions it can support.
- EPA Radon Action Levels ExplainedTwo numbers drive nearly every radon decision: 4.0 pCi/L, where the EPA recommends action, and 2.0 pCi/L, where it suggests considering it. Here is what sits behind them.