Most radon mitigation fans fall into two categories: high-suction or high-volume, except the dual-category Rn4EC. High-suction radion mitigation fans typically move more air when encountering high resistance. These fans work best with a difficult or smaller pressure field extension and “tight” soil conditions. Fans in this category include the Rn4EC and the GP series by RadonAway. These high-suction radon mitigation fans perform better than other fans in “tighter soils” or low pressure field extension. For accurate fan sizing: utilize a micromanometer, the pressure field extension diagnostic kit, or call PDS!