10 Radon Reduction System Questions

It’s important to fix the radon problem in your house if a test shows a concentration of 4 picoCuries per liter (pCi/L) or higher, so buy a test kit. You can get one at a home center for about $10— plus a $40 lab fee—and perform the test yourself. You just let the tester sit in your house for a few days and then mail it to a lab for analysis. Electronic radon monitors that monitor continuously for radon are available online for about $130 and don’t require a lab.

A fan pulls radon gas from beneath the floor and exhausts it outside. In cold climates, it’s better to run the pipe inside the house rather than outside.

Make a quick phone call to your town’s building department to ask about local code requirements, permits and inspections. In some areas, only licensed pros are allowed to install systems.

In most cases, you’ll want to locate the PVC pipe that sucks radon from under your concrete floor near an exterior wall so it’s out of the way and easy to route outside. And this is also where sump pump basins and footing drainpipes (aka “drain tile”) are located in some homes—perfect places from which to suck radon. If you don’t have a sump basin, you’ll have digging to do. If you use the sump basin as your suction point, be sure to seal around any pipe and wire penetrations in the lid. Special supplies for dealing with sump basin lids are available online at indoor-air-healthadvisor.com, or do an online search for “radon sump lid.”

It’s much easier to route the pipe outside the house, but that can cause a problem in cold climates. Condensation can form inside, causing ice to build up and stop the fan from working.

If you'll be routing your pipe outdoors, it's no big deal. Just run it up along an exterior wall. But running pipe indoors can be a real nightmare. Most professional installers in cold-weather areas try to avoid condensation problems by routing the pipe up through a closet or finished garage and to a fan in the attic that blows the radon out above the roof. Be ready for a big, dusty mess if you have to route your pipe indoors. Also keep in mind that the pipe has to terminate 12 in. above the roof and be at least 10 in. away (horizontally) from any dormer windows. Ask your city's building department about any additional requirements.

If you’ll be mounting the fan outside, put it in a place where you can get electricity to it easily. If it’s indoors, the fan must be located in an unfinished attic. Never install the fan in your basement or any living space because, if there’s ever a leak, the fan could pump highly concentrated radon right into your home.

The toughest part of any electrical job is getting cable from point A to point B. If there's a junction box nearby that you can extend the circuit from, you're golden. If not, you might be spending lots of time fishing cable to where you need it. Fans draw very little power—usually less than 100 watts—so you can tap any nearby circuit. You can also hardwire a fan or plug it into an outlet. In an attic, it's best to install an outlet because it makes replacing the fan easier. Outside, it's best to hardwire the fan using watertight conduit.

You may not know what kind of base material you have under your concrete slab until you punch a hole in the floor. And soil conditions affect how readily radon flows underneath the slab, so don’t buy a fan until you know what you’re dealing with. You’ll need to provide this information when you buy a fan from an expert.

Radon fans cost $140 to $250, depending mostly on size. Some radon mitigation systems require a big, powerful fan. Others work fine with a smaller model. Sizing a fan requires expertise, so we strongly recommend that you buy from an expert who will ask questions and supply you with the best fan for your situation. As well as exchange the fan for a bigger one if the smaller one doesn’t fix your radon problem. One such expert is Val Riedman, a professional radon system installer who runs a website where you can get more DIY information and buy supplies. The Family Handyman editors have purchased fans from him. Visit Healthy Air Solutions for more information. Owner Val Riedman also contributed to this article.