National Radon Program Services, operated by Kansas State University through an EPA cooperative agreement, lists a $20 short-term kit and a $30 long-term kit. Both prices include laboratory analysis. Shipping upgrades and New Jersey’s additional state fee can change the final amount.
DIY and professional testing compared
| Option | Current cost signal | Best fit |
|---|---|---|
| Short-term mail-in kit | $20 through the KSU program | An initial home check when results are needed soon |
| Long-term mail-in kit | $30 through the KSU program | A better estimate of the year-round average |
| Professional measurement | Local quote required | Real-estate transactions, documented placement, or continuous monitoring |
Prices checked September 3, 2026. Retail, shipping, state fees, and professional rates vary.
Short-term versus long-term tests
EPA’s Home Buyer’s and Seller’s Guide defines short-term testing as two to 90 days, depending on the device. All radon tests should run for at least 48 hours, and some devices require longer. Short-term testing is useful when you need an answer quickly.
Long-term tests remain in the home for more than 90 days. Because radon varies from day to day and season to season, a long-term result is more likely to represent the home’s year-round average. The KSU program’s current long-term kit is designed for three to 12 months.
What the kit price should include
- The test device and placement instructions.
- Laboratory analysis, when the device is a mail-in kit.
- A clear return-shipping process and deadline.
- A written result in pCi/L, with the test dates and device information.
Check the terms before buying a low-priced retail kit. Some products include laboratory analysis while others charge a separate fee. Expedited shipping can also add cost when the device must reach the laboratory within a limited period.
When professional testing may be worth it
A qualified measurement professional can select the appropriate device, document placement and test conditions, and use equipment designed to detect interference. That added documentation can be useful during a home sale, after disputed results, or when a large building requires several devices.
Professional service prices vary by market, building size, device, turnaround time, and the number of measurement locations. Ask whether the quote includes the device, travel, report, expedited results, and any follow-up measurement.
Testing after mitigation
A post-installation test verifies whether the system lowered the radon concentration. Do not assume a running fan proves that the home is below the action level. Clarify whether your contractor includes an independent post-test or expects you to arrange one. The EPA also recommends retesting at least every two years after mitigation.
How to interpret the result
The EPA recommends fixing a home at 4 pCi/L or higher and considering mitigation between 2 and 4 pCi/L. Because no level of radon exposure is known to be completely safe, the goal is to reduce the level as much as reasonably achievable. Follow current state requirements when they differ or add testing rules.
Sources
Current kit pricing comes from National Radon Program Services at Kansas State University. Testing durations and procedures come from EPA’s Home Buyer’s and Seller’s Guide to Radon. Action-level guidance comes from the EPA radon action-level page.