Clarity for your home.Choose the measurement period from the purpose and testing instructions. Plan enough time for the chosen procedure and each device’s startup instructions.
EPA's two testing categories
The EPA Citizen's Guide, pages 5–6 describes short-term tests lasting two to 90 days, depending on the device, and long-term tests lasting more than 90 days. Longer tests are more likely to represent a home's year-round average because radon varies over time.
Record the start date and any interruptions, then read the displayed average alongside that period.
What a first-reading claim means
| Device documentation | What it says | How to use that information |
|---|---|---|
| Home 2 manual | First 24-hour radon average after 24 hours of samples | Start building the average; choose the required test duration separately |
| RadonEye product page | First reading after ten minutes | Treat it as an initial reading; continue for the appropriate test period |
| View calibration guidance | Different sensors have different initial adjustment requirements | Check the adjustment period for the sensor you plan to use |
Sources: Home 2 manual, RadonEye documentation, View calibration guidance. Use the device instructions together with the appropriate US testing guidance.
Follow up on the result
EPA's Citizen's Guide calls for follow-up when an initial short-term result is 4 pCi/L or higher. If it exceeds 8 pCi/L, take a second short-term test immediately. A long-term follow-up at 4 pCi/L or above calls for radon reduction. After two short-term tests, EPA advises considering reduction when their average is 4 pCi/L or higher. Follow the complete sequence on page 6 and seek qualified help for reducing elevated levels.
For a completed test, keep the measurement dates, method, location and report together. A screenshot without those details can be difficult to interpret later.
A property transaction has its own requirements
The EPA Home Buyer's and Seller's Guide, March 2024 gives transaction-specific options, placement guidance and precautions against interference. Confirm applicable state requirements, the procedure and accepted report with your provider.
Before you start
Establish whether you need an initial household test, follow-up, ongoing observation or a transaction result. Then choose a suitable method, identify the test location and record the start date. If a manufacturer recommendation appears to conflict with the applicable protocol, resolve it with the relevant radon program or qualified tester before proceeding.
Documentation used
- US EPA — A Citizen's Guide to Radon (2025)US public guidance · checked 2026-10-12
- US EPA — Home Buyer's and Seller's Guide to Radon (March 2024)US public guidance; property transactions · checked 2026-10-12
- Airthings — Corentium Home 2 user manual v1 (June 2025)Manufacturer instructions · checked 2026-10-12
- Ecosense — RadonEyeManufacturer specifications · checked 2026-10-12
- Airthings — View calibration period (April 2026)Manufacturer instructions; not an EPA testing protocol · checked 2026-10-12