The cost for a radon mitigation system typically ranges from $800 to $1,500, with an average around $1,000. The final price depends on several factors, including the size of your home, the severity of the radon issue, and the type of system required. Your home's foundation type also significantly impacts the cost. For example, sealing and ventilating an unfinished basement might cost around $4,600, while encapsulating a crawl space without a foundation slab can range from $1,500 to $15,000.

Radon enters your home when warm air begins to rise and exits through the roof, creating a vacuum that pulls cooler air from under the foundation. Part of that air is radon, which is an invisible, odorless gas that develops naturally when radioactive particles are deep within the ground. Those particles usually come from decaying matter in soil and rocks.

Radon is present almost everywhere but, like sunlight, the concentration levels and how often you are exposed to it have a large part to play in just how dangerous it is. There are levels of radon that are acceptable inside a house, but above a certain limit, radon becomes a serious radioactive hazard that is a known cause of lung cancer. In fact, radon exposure is the number two leading cause of lung cancer (after smoking).

No level of radon is technically safe, but since it is naturally present everywhere, it is impossible to avoid entirely. The average radon level in homes across the United States is 1.3 picocuries per liter (pCi/L). The Environmental Protection Agency (EPA) recommends taking action to reduce radon levels if your home's test results are between 2 and 4 pCi/L or higher.