Radon testing costs $125 to $400 on average for a professional radon inspection. However, costs may reach $700 for large, multi-story homes that require multiple testing devices.
Most radon inspectors use an electret ion detector, which features a statically charged Teflon disc that attracts ions generated by radon decay. These ions reduce the electrical charge of the disc, and the reduction can be measured in a lab to calculate the home's radon levels.
A home radon test kit costs $10 to $50, including professional lab analysis. Prices depend on whether you select a short-term or long-term test.