EPA strongly encourages radon testing in all homes, however, this is not a requirement for Indoor airPLUS qualifications. For newly constructed Indoor airPLUS homes located in Radon Zone 1, a passive radon mitigation system is required at a minimum. This creates the ability to easily install a radon vent fan (for an active system) if the home were to be tested at or above 4 pCi/L, the EPA’s radon action level. For more information about radon-resistant construction techniques, visit EPA’s webpage dedicated to Radon-Resistant New Construction (RRNC).