How does a radon mitigation system work?

If your home tests high for radon, you’ll likely wonder what steps can be taken to reduce it. The good news is that a radon mitigation system is a simple way to lower your radon levels and keep your loved ones safe from radon-induced diseases. Let's see how does a radon mitigation system work below.

How does radon enter a home? 

Radon is a naturally occurring odorless, colorless, and tasteless radioactive gas that enters homes due to a phenomenon called the stack effect. Higher-temperature air is less dense and tends to rise, while lower-temperature air is dense and tends to stay low. As hot air rises and leaves the house, cooler air gets sucked in from below the foundation. 

(Credit: Green Collar greencollarma.com)

Because the foundation is the closest to the ground where radon gas is the most concentrated, the stack effect draws the gas into the home. 

How is radon gas removed? 

The most common and effective radon mitigation method is sub-slab depressurization (SSD). The goal of SSD is to create negative pressure under the foundation of the home. This negative pressure helps prevent soil gases from entering the home. This is done by creating a suction pit beneath the home’s foundation where the radon gas collects, installing a series of pipes connected to the suction pit to keep the gas from entering the home, and sucking the gas out of the home to the outside air using a radon fan. 

Types of radon mitigation systems

There are two basic types of radon mitigation systems: interior and exterior. Both systems use SSD, but the main difference is where the system is installed.  

Interior radon mitigation systems

Interior radon mitigation systems are installed inside the home, usually in a chase, garage, or closet. The pipes connect the suction pit to the radon fan located in the attic. Because of this, the only visible portion from the outside of the home is the roof jack. This is the primary advantage of an interior system; however, interior systems tend to cost a little more than exterior systems because they tend to be more labor-intensive.  

Radon pipe connected to the suction pit
Radon pipe exiting into the garage
Radon pipe connecting to fan
Radon pipe connect to roof jack

Interior systems can be installed during or after the construction of the house. Many homebuilders in Utah now offer radon mitigation systems as options when building the house. If your home is already built, certified installers can usually retrofit it to accommodate an interior system. If the house's layout will not accommodate an interior system, an exterior system can be installed. 

Exterior radon mitigation systems

Exterior radon mitigation systems are installed partly inside the house and partly outside. Like an interior system, exterior systems start at the home's foundation, where a suction pit is dug to collect the radon gas. The pit is connected to piping that exits the house a little above the ground level. A radon fan is connected to the pipe, and a rain gutter is installed from the fan to the roof line. A rain gutter is used simply for aesthetic reasons (to match the existing rain gutters on the house). 

Radon pipe exiting the house to the fan
Pipe ties into rain gutter and exits at the roof 

Who can install a radon mitigation system? 

Because radon is a Class A carcinogen, only a certified radon mitigator should install a radon mitigation system. You can see who is certified in Utah by going to the National Radon Proficiency Program’s website

When selecting a radon mitigator, ensure they are certified, check out their Google Reviews, and be leery of below average pricing (some mitigators will quote low and then charge more on the day of installation). Remember you’re dealing with a radioactive gas - don’t cut any corners.