A passive radon mitigation system is a system without a fan. This type of system may have been installed when your home was being built. In Minnesota, if the building permit for your home was obtained after June 1, 2009, it should have a passive radon mitigation system.

To check if your home has a passive radon mitigation system, take a look in your basement. In the mechanical room, storage room, or under the stairs, you should see a 3-inch wide white or black plastic pipe that comes up through the concrete floor or sump basket cover, then goes up to the ceiling and disappears inside an interior wall of your home. The pipe should have a label that says, “This is a component of a radon mitigation system, do not tamper with or disconnect.” Or, the installer may have simply written “Radon” on the pipe.

Just because your home has a passive radon reduction system, it doesn’t necessarily mean your family is safe. Studies have shown that most passive systems only reduce radon levels by 50 percent. In fact, when high winds blow over the top of the vent pipe on your roof, radon levels can actually increase.

Fortunately, it is possible to convert a passive radon mitigation system into an active one. We do this by cutting out part of the vent pipe in the attic and adding a radon fan, which creates the necessary suction under your home.

If your home was built before June 2009, you’ll likely need a drain tile depressurization (DTD) or sub-slab depressurization (SSD) radon reduction system. Both are active radon mitigation systems that will create a vacuum under your home to give the radon a proper escape route.

DTD systems utilize existing drain tile below the concrete floor of your home to create an easy path to pull the radon gas into the mitigation system. They are typically very effective at reducing radon concentrations and often the easiest and least expensive systems to install. However, in homes with drain tile, we often have to seal multiple air leaks. A finished basement makes it even harder to seal air leaks, meaning a more powerful radon fan may be needed. These high-flow systems do come at a price though, as it costs more to run a bigger fan and replace the conditioned air that is drawn into the radon system and exhausted outside.

If your home doesn’t have a drain tile system, then we’ll install an SSD system. They work by creating suction in a void created below the floor to draw the radon-laden soil gas into the radon system. The function of an SSD system is similar to that of a DTD system, however, instead of running collection points through a drain tile system, we drill directly into your home’s concrete floor. SSD systems often require more suction points and many also require a high-suction fan to effectively and efficiently remove radon from your home. Since they’re more complicated to test and design, SSD systems are often more expensive than DTD ones.

To know if your active radon mitigation system is working, we install a U-tube manometer that measures the suction of the fan. If the fluid levels in the U-tube are different, the radon fan is working. If the fluid levels are equal at zero, the fan is not working, in which case you should call for service. In addition to the manometer, we offer a low airflow alarm that starts to beep within 30 seconds if the airflow in the pipe drops, indicating a problem.

We also provide you with a post-mitigation radon test kit to ensure the radon levels have dropped. This test can be run as soon as 24 hours after the system has been turned on. If you sign up for one of our service plans, we’ll even send you a long-term test kit every year to ensure your radon levels remain low.

With any active radon mitigation system, the key to reducing radon levels as low as possible is to create a vacuum under your entire home. The only way to know if we’re achieving this is to take the time to do the diagnostic testing.

For example, if we create a suction point in the mechanical room in the basement, we need to confirm that the vacuum reaches the bedroom on the far side of the basement. If it doesn’t, the radon in your home is not being properly mitigated. Our diagnostic testing process ensures everyone in your family is protected from radon, regardless of where they are in your home.

We don’t take a one-size-fits-all approach when we select your home’s radon fan. An undersized fan may not lower your radon levels adequately, and an oversized fan costs more to run. Through our diagnostic testing process, we ensure we are installing a fan that’s right for your home.

Code requires us to install your radon fan in an unconditioned space. An unconditioned space is one that you don’t heat or cool, which is often an attic space or the exterior of your home.

We often take a phased approach to mitigating crawl spaces. Treating a crawl space can be expensive, but not always required.

First, we’ll design and install your home’s mitigation system to treat the basement. Then we’ll retest the radon levels in the basement and the room above the crawl space. If they are both low, then no further action is needed. If the level above the crawl space is high, we’ll recommend mitigation.

If left unaddressed, the radon from the crawl space will rise up into the living spaces above it, putting your entire family at risk.