What happens if you run your ICE vehicle in your garage, turn on some Morrisey, and close the garage door? Nothing good right? Carbon monoxide poisoning is imminent. The same logic applies to indoor radon fans.
A radon fan’s job is to exhaust radioactive gas, the airflow direction is up. If you put a radon fan inside and the exhaust side is compromised, not only would you not get rid of radioactive radon gas, but you may inadvertently fill your home with hundreds of cubic feet of radon gas per minute!
You might say: Brent, that’ll never happen. I’m here to tell you it does. People that put radon fans indoors often make other mistakes. A cracked pipe, a poorly installed coupler or support strap is all it takes to create a huge problem.
If you’ve read my other posts, you know that most homeowners neglect the most important radon mitigation maintenance: testing. If you don’t test regularly and have an indoor radon fan you’re gambling with your life. Under all US codes the only acceptable places for radon fans are outside the thermal envelope of the home. This typically means: attics; sides of homes; or in garages with no living spaces above.