I agree with Henri about the Femto-Tech 510. Its been a reliable workhorse for us for over a decade. I have pretty much "retired" my Sun Nuclear 1027 due to its need for AC and its "low counts". Most home inspectors use them here but ONLY because they "cost less". I doubt any of them know what "counts" are! And most terminate them just after 48 hours (because that's the "absolute minimum: the EPA says you must do for a "valid test". But what they don't communicate well is that you have to allow 12 hours for "closed house conditions". I don't think many home inspectors here know what that is. We always let ours run for 72 hours. And Henri, you are right about the high counts on the RadonEye pro. Femto Tech is suppose to release some new units soon. But I sure hope they are Bluetooth compatible and price competitive or I may have to jump ship!

My experience over 20 years is that radon maps are like a "light posts". They should be used for "illumination" NOT "support!" Consequently, I prefer to tell everyone that EVERY structure has radon! But the ONLY way you will know "how much" is to TEST! I would argue this eliminates all the "speculation" about whether a house is in a Zone 1, 2 or 3 county. As mitigators, most of us have probably installed systems in Zone 2 and 3 homes that came back at "double digits". NO home has a problem with radon until it's tested! And homes constructed by builders with passive piping need NEVER be tested, right? (haha). I'd be interested to see a stat that showed how many homes out of a 100 with fans installed on the pipes STILL came back HIGH? :scream:

What I don't quite understand about the "mandatory" Radon System Alarms is that WHY is the warranty on them only "2 years" when most fans are warranted for FIVE? I personally see that benefit of "traditional electronic alarms" in homes where builders installed passive piping (but only thought of it as "piping required to be installed because building code required it). The vast majority of builders who install this piping "assume" that it will take care of the radon under the slab because it allows it to "rise and exhaust" like helium does! But WE know that radon is "heavier" than air and must have a "vacuum" to draw it out. My county building code requires passive pipe and they even provide an "EPA schematic" of slab and crawl space systems. Each reference a "warning device". However, NO builder makes any sort of provision for that. So when a house is later tested and elevated levels are found and a fan is installed, there is no way for the "future homeowner" to check and see if their fan is working without out climbing up to the attic! I, personally, like the manual manometers because you don't have to depend on "electronics" for them to work. We all know how power strips, modems, routers and TV's get "fried" due to line surges (or lightning). So I have a had number of homes that I "opened up the wall" in front of the pipe and installed a manometer on them with a window/door in the dry wall. But I will admit this is usually only done in closets or areas of the home where "cosmetics" don't matter. Who wants a see-through door in a living room wall?