Radon is a cancer-causing radioactive gas. It comes from the natural decay of uranium that is found in nearly all soils. It typically moves up through the ground to the air above and into your home through cracks and other holes in the foundation. Any home can have a radon problem. In the U.S. it is estimated that nearly 1 out of 15 homes has an elevated radon level.

All homes contain some amount of radon. Radon levels can be reliably reduced to less than 4.0 pCi/L. Effective and durable systems have been developed for reducing radon.

The fan cannot "suck out" all the radon gas from underneath the slab and none from outside the walls. But soil is not perfectly permeable to radon gas and over time, the gravel under the slab tends to silt up. RadonSeal will reduce your radon level further by sealing both the slab and the walls. It will also lower the operating costs of the fan-based system ($150/year on average) by reducing the energy losses in heated/cooled air now pulled in a reverse direction through the slab.

It should be emphasised that when the radon concentration is high, it does pose a serious risk to your health. Radioactive decay of radon forms particles called 'radon daughters'. If you breathe these in they damage your lung tissues. Many health studies around the world have linked radon with lung cancer.

When uranium decays, it becomes radium, and when radium decays, it becomes radon. Uranium is found in small quantities in all soil and rocks, but amounts vary from place to place. There can be marked variations even over small areas, and may be different levels of radon even between neighbouring buildings. Granite contains small amounts of uranium, which is why the South West has slightly higher levels than other parts of the UK.

Testing is the only way to know if you are at risk. Radon gas is invisible and odorless. Both long- and short-term testing devises are available. A homeowner should consult a radon professional to determine what type of test is best suited for his situation.

Radon gas increases the risk of getting lung cancer. Your chances of getting lung cancer from radon gas depend on factors such as the home’s radon level, the amount of time you spend in your home and whether you are a smoker or have ever been a smoker. Recent studies estimate that between 15,400 and 21,800 deaths per year are attributable to radon gas.

The test should be conducted in the lowest livable level of the house which is usually the basement. The test kit should be placed at least two feet above the floor. All windows and outside doors on the level you are testing should be closed during the test. All windows and outside doors should be closed 12 hours prior to and during the test period.