Most of the cost is the installation of equipment in the existing home. In areas of the country that have a lot of radon, it's not uncommon to install the equipment during construction of the house foundation, which then only adds a few hundred dollars to the total cost.
> Radon-resistant new construction (RRNC) typically costs a builder between $250 and $750. RRNC could cost less than $250 if the builder already uses some of the same techniques for moisture control.
> Radon-resistant new construction (RRNC) typically costs a builder between $250 and $750. RRNC could cost less than $250 if the builder already uses some of the same techniques for moisture control.
https://www.epa.gov/radon/radon-resistant-new-construction-h...