When is it appropriate to use a low voltage radon fan mitigation system?

CLASS Matters

Low voltage radon mitigation systems (sometimes called radon “plug and play” fans) save time and money for the conscientious radon professional or DIYer.  Be sure your low voltage system is CLASS II or it may get called out on your next inspection.  Certain classifications and certain jurisdictions require an electrical permit be pulled.  

Fan Placement, Permits, and Licensing

Radon fans are often placed in areas with no readily-available power.  Since the builder didn’t plan for radon, they likely didn’t plan to have power where the radon fan ended up.  A Class II low voltage radon system allows the installer to power the fan immediately without a costly electrical consult or a timely permit pull (in most jurisdictions).  

Radon fans are only acceptable outside the thermal envelope of the home*.  The three most common places are attics, garages, and on the side of your house.  If you see a radon fan in your basement, crawlspace, or mechanical room, then you’ve got a red flag* (more details on why here).  It’s very costly and labor-intensive to install PVC through finished levels of the home, so contractors penetrate rim joists and you’ll often find radon fans at ground level outside a home.  There is very rarely available power in these areas**.  

Radon contractors that run their own wiring without an electrical license or without a permit are BREAKING THE LAW.  This is a very common corner cut in our industry and it is very dangerous.  Do not let a professional run electrical conduit in your home without asking for a license.

International Standards

International radon standards only allow a 6′ cord in attics and garages.  Six foot cables may seem like an easy solution for outdoor fans.  What if you get lucky and there is an outlet right by the fan?  It is still not allowed.  The reason being: cords get unplugged, usually in a hurry.  A landscaper needs it for a weed whacker or shop vac.  The homeowner wants it for Christmas lights.  The problem is: they very often forget to plug the radon fan back in.  Since radon is colorless and odorless, this powerless system can exist for months or even years, exposing the occupants to this dangerous carcinogen all while they think they’re safe.

These outdoor outlets are also often GFCIs.  GFCIs trip often, especially outdoors.  Your fan may not be powered 24/7/365 and that’s a big problem–especially if you’re one of the thousands of systems in American without a radon alarm (learn here).

Extension cords

Why can’t I just use an extension cord?  Radon fans are rated as small appliances so 110V+ power cords longer than 6’ are not allowed under NEC (National Electrical Code).  Extension cord powered systems fall under my list of RED FLAGS.  Since our KTA low voltage system is class II 24V, it can be run through finished spaces and exterior walls without a permit (in most juristictions).  Do not run LV cabling through a firewall without a proper fire collar.

KTA 1.0 and 2.0 power supply boxes should be placed inside the home–mechanical rooms and garages are the most common placements.  They should be in a conspicuous place so that the occupants can monitor the system and note any changes or alarm states.  With up to 100’ of low voltage cabling, you can almost always make it to your legal fan placement outside the thermal envelope of the home.  

The 2.0 system is recommended as it has an audible and visual alarm.  Should something go wrong: the KTA lets you know!

Save time and money with the KTA low voltage radon fan system.

*in the USA.  If you place a radon fan indoors, and the exhaust of the system is compromised, then you may actively fill your home with radioactive gas.  Since radon gas has no taste or smell, you won’t realize this grave mistake until you perform another radon test.  This is why radon fans must be placed with the full exhaust branch outside the home’s thermal envelope.  If the suction-side fails, your radon levels may rise to baseline, but you will not add extra soil gas to the home.

**Radon pros may pull power from an existing branch electrical line; however in most parts of the USA this is only legal with an electrician’s license and a local permit.  Since electricians make more money than radon professionals, very few contractors carry both licenses.  Be sure to check the national and state certifications of any contractor you allow to work on your home or radon system.  Full voltage radon systems need to have a tamper-proof locking switch and cannot be plugged into an exterior outlet.  Too much risk of the cord being unplugged and never plugged back in.

Thank you for reading!