Posted on

What is a passive radon system?

Passive radon systems or “radon-ready” systems—as they should be called—are pre-plumbed radon systems for a building. They do not function unless there is a radon fan added to them*. This is why it is my personal mission to remove the term “passive” from the nomenclature. It implies that the system works as is. If you have high radon levels, you’re gonna need a fan no matter what. See this new home my good friend built. He was under the impression that he had a radon system and almost didn’t test! Good thing he knew me. We tested his passive radon system and he had a whopping 11+ pCi/L, nearly three times the EPA action level! He could’ve lived decades in that home thinking he was safe.

Always perform a radon test on a passive home. This is why EPA recommended testing is important and can save your life. You don’t test a home once; you test at minimum every five years.

Why should you build a radon-ready home?

There are many benefits to building radon ready. In my opinion, the biggest benefit is: no loud, ugly radon fan on the side of your house. Yes, we know they’re loud, we know they’re ugly, but they’re better than stage IV lung cancer.

In Zone 1, high-risk states like Colorado, Iowa, or North Dakota, your chances of having dangerous radon levels are higher than having low levels. So if you’re a gambler, you’re betting against the house: literally. Even if you don’t have high radon levels, many homeowners choose to add a low-wattage fan to the system for the benefit of increased airflow under the slab. A dry slab is good for the home’s foundation and it can eliminate musty basement smells.

Other benefits of radon-ready homes are: more energy-efficient radon fans can be installed since you have perfect PFE; smaller fans are quieter fans; fan location is often in garages or attics away from occupants–again quieter; increased home value from having a radon system; and again, radon-ready systems are much more cosmetically appealing than post-construction radon systems.

Passive Radon-ready systems are the future of homebuilding. Don’t get left behind, ask your builder or realtor about radon-ready homes today! PDS offers free system designs at

*Passive radon systems can function in very specific weather conditions due to the stack effect. In North America, these weather conditions do not exist 12 months out of the year, which is why I believe the term is dangerous. If you insist on trying to use your system passively, I cannot recommend a continuous radon monitor more. Watch your radon levels fluctuate with weather patterns and see for yourself.  Passive radon systems include those called out in IRC Appendix F, ANSI/AARST RRNC 2020 and AARST-ANSI CC-1000-2018