Only Short Term test kits require Closed House Conditions. Closed House Conditions help ensure that radon is detected if it is present in the building.
To follow Closed House Conditions, ensure that:
- All exterior doors and windows of the entire house are kept closed for at least 12 hours before testing and for the duration of the test. Normal entry and exit is fine, but exterior doors should not be left open for long periods of time. Interior doors should be used as normal.
- Heating and cooling systems can be run, provided that they are working in some sort of “re-circulation” mode where they are not having inside and outside air exchange.
- If you normally run a dehumidifier, then you should run it during testing as normal.
- Fans venting air to the outside (like stovetop or bathroom fans) should be used as little as possible.
- Fans circulating air inside the house should be fine to use, but be careful not to expose the radon sampler to a lot of moving air. Make sure that your fan or vent is not blowing at the sampler, and avoid placing it right next to your fan or vent.
If you didn’t test under Closed House Conditions, that doesn’t invalidate your test, but be advised that your results may not be as accurate as they would have been if tested under these conditions. If your house met these requirements during your test, then mark “Yes” for Closed House Conditions!