You Can't
Hold Your Breath
Forever.

By regulation, radon fans must be located outside of the conditioned space of the home.

The regulation stipulates that the exhaust must extend above the roofline. The idea is to keep the exhaust gas from coming back into the house or impinging on patios, walkways, play areas, etc. There are three basic requirements: The exhaust must be

(a) at least ten feet off the ground,
(b) above the eave (not necessarily the edge) of the roof, and
(c) either ten feet away from, or two feet above, windows.

As long as the system is running, the air exiting the pipe keeps rain and bugs out. The system exhaust must be vertical, and upward. The rest of the system is designed so that it pitches back down toward the suction point, so that any water in the system drains back into the soil. Caps and other diverters can cause freeze-up problems from condensation when it’s cold out. Did you know: radon systems can expel hundreds of gallons of water vapor each year?

PVC piping is the most suitable material for the job. Metal downspouts are not intended to be used for gas exhaust applications, and the joints cannot be permanently sealed (they require frequent re-sealing). Downspouts also tend to ice up in the winter, disabling the system just when you need it the most.

Our standard sump covers are transparent, so you can shine a flash light into the sump pit to verify that the sump is working.

The idea is to put a vacuum on the draintile that surrounds the foundation. The builder put it there to collect water, but we can use it to collect gas too. Because the draintile is connected to the sump, we have to seal it to hold the vacuum. As gases come percolating through the soil, they are drawn off into the draintile and then into our radon piping. Instead of passing through the house, they are confined to a small tube. Elegant.

As discussed in FAQ 6, the sump is a means to an end. Your pump's float valve must be set low enough to keep the draintile dry. If the draintile is allowed to fill with water, it will no longer function as a vacuum collector.

Also, if you have a pedestal style sump pump (the kind where the motor sits above the basement floor) it generally needs to be replaced so that the airtight seal can be maintained.

How much good news can you stand? In our experience (valid for Michigan, at least), the homes with the very high initial readings have been the easiest to fix, and have had the lowest post-mitigation radon levels. Here's the reasoning. Very high radon levels mean very loose soil conditions, and in these situations our system's vacuum will cover the entire footprint of the house, reducing radon levels to near outdoor levels. One recent Ann Arbor home began at 216 pCi/l and ended at 0.6.

The tough homes are usually those with slightly elevated radon levels, frequently built on clay. There all the radon might be coming in from one fissure, and the tight clay might prevent our system vacuum from reaching it. We could take several tries and several suction points before finding the right location. We are very stubborn, and always win. More than 10,000 successful systems so far.)

Promises are only as good as the company making them. More than 95% of our installations systems wind up below 2, and all of them are below 4. We simply will not promise something that we cannot deliver on 100% of the time. Here are two exercises for you:
Check out our 20 or 30 most recent test results using the window into Air Chek's database, and see how many times a value below 2 is listed. (Don't be scared off by the occasional high number; these are almost always pre-mitigation screening tests.)
Check out the credentials and track record of the Company making the promises. Some companies will simply walk away (and hopefully return your money) if they can’t fix your home. What happens if your home is one of the tough ones?
In some situations it simply may not be possible to get the radon levels much below 4 pCi/l. After all, that's why EPA chose 4 as the Action Level. They were required by law* to choose the lowest level that could be achieved on the vast majority of homes. They considered 2, and rejected it.

* Title III of the Toxic Substance Control Act, 15 USC 2665. Signed by President Reagan, by the way!

National surveys of EPA-listed companies have shown that the typical radon system warranty runs from 1 to 5 years. Lifetime warranties are often vague or misleading (the lifetime of the fan, system, homeownership, the company, etc?). Keep in mind that radon can change based on changes you make to your home, and that the typical life expectancy of the radon fan (the only motorized component of the system) is 5-10 years, and most manufacturers only warranty them for 5.