When should a test for the effectiveness of a radon mitigation system be conducted after completion?

The testing for the effectiveness of a radon mitigation system is optimal when conducted between 24 hours and 30 days after system installation. This timeframe is crucial for ensuring that the radon levels are accurately measured after the system has been put in place and has had a chance to reduce any elevated radon levels within the structure.

Conducting the test as early as 24 hours post-installation allows for an initial assessment of the system's performance. However, waiting up to 30 days provides a more representative measure of the system's effectiveness under varying environmental conditions, such as changes in temperature or humidity that can influence radon levels. This extended period can also ensure that any transient effects from recent construction work have settled down, allowing for a more stable and accurate measurement.

In summary, testing within this range gives a comprehensive understanding of how well the mitigation system is functioning in the long term, facilitating necessary adjustments or affirmations of the system's efficacy.