If your house has dangerous levels of radon, it is importan to install a radon mitigation system. A radon fan is part of such a mitigation system. A common question many DIYers ask is whether they can install the radon fan in the basement of their house.
A radon fan cannot be installed in a basement. As per building codes, a radon fan should be installed only in attics, garages, or outside the house. One should not install it in a conditioned area of the house or below a living area.
You may be wondering what the point of dong this is. Most people prefer to hide the fan and the mitigation system from plain view for aesthetic reasons. Many also believe that seeing mitigation systems outside lower home value. So when people like you and me have plenty of reasons to install the radon fan in the basement, why does the US building code says it should not be installed there?
Why you shouldn’t install a radon fan in the basement?
Like I said before, people want to install the radon fan in the basement, away from outside view for aesthetic reasons. But the building codes in the USA prohibits this.
You shouldn’t install a radon fan in the basement because any leakage in the mitigation system can leave the basement with terribly high levels of radon. Such a leak can increase the radon levels in the basement to hundreds of pCi/L, which is much more dangerous than the normal high radon levels see in homes.
As you know, a radon fan forces radon gas out from beneath your basement. The air passing through the radon pipes has high amounts of radon in it, often measuring as much as 1000 pCi/L. Imagine what happens if there is a leak in the system! Your house will be flowing with air having radon contents a hundred times more than the safety limits. As radon is colorless and odorless, you will not know about the leakage. Since this leakage can go undetected even for years, you and your family will remain exposed to dangerous health hazards.
This is the reason why the government prohibits the installation of radon fans in the basements. You can install them outside your house, in the attic, or in a garage that doesn’t have any living areas above. (Page 14 of source)
But isn’t this rule a bit outdated?
This rule was made when people were using galvanized pipes in their homes. These pipes had more chances of leaking than the 1/4 inch PVC pipes used today. Also, you can buy radon level monitors for your home, which constantly monitor the radon levels in your home. If the radon levels go above the safe value, which is 4 pCi/L, the monitor will notify you.
So I personally think that this rule is a bit outdated. For example, in Canada, you are allowed to install a radon fan in your basement!
Why is it allowed in Canada to install a radon fan in the basement?
In Canada, you can install a radon fan in the basement. In fact, the building codes recommend installing the fan there. This is because Canada has freezing temperatures almost all times of the year. So, if the radon fan and the pipes are installed outside, there is a good chance that the condensations in it get frozen up, damaging the mitigation system.
To protect the mitigation systems from freezing up, the building codes in Canada recommend installing radon fans in the basements of houses. Another difference in the Canadian code is, the exhaust of the radon system is at the ground level as opposed to the US system, where it should be vented above the roofline. In Canada, if the radon fan is installed in the basement, you can run a horizontal pipe from the fan and vent the gas just outside. But if the fan is installed in the attic or the garage, the exhaust should go above the roof.
Why is it recommended to install radon fans in attics, garages, and outside?
As you know garages, attics, and outside the house are not conditioned spaces of a house. These places have plenty of air circulation. So in the rare event of your radon system leaking, the excess radon gas will be vented outside. Moreover, this will prevent the gas from getting ino the conditioned living areas of the house where it will be circulated thorughout the house causing dangerous health risks.
PS: There are homes with conditioned attic spaces. If your attic is conditioned, do not install your radon fan there.
What to do if you bought a house with a radon fan installed in the basement?
It is not unheard of people buying a new house without doing a radon test, or finding that the previous owner had teh radon fan installed in the basement. Even though radon testing is part of the home inspection process not all home inspectors do it unless you ask for it. This can leave you with elevated levels of radon in your home.
Installing a radon fan in the basement is a common DIY mistake. Licensed professionals would never install the radon fan in the basement. If the previous owner of your home installed the fan in the basement, and you bought the house without checking it, your only option is to take everything out and install the fan on the outside. Many people think that adding a radon monitor will solve the problem. Their logic is that the radon monitor will alert them when the levels get high. Even though this is true in theory, the radon monitor can malfunction. It may not happen today or tomorrow, but may be five years later! There is no need to take such a risk when you can get the fan installed outsiude the house.