What is Radon? What does it do? How does winter conditions effect radon in my home? Check out this week on the KFGO Morning Crew, Lars talks radon — how it effects you and your home, and what you can do about it.
Schedule a professional home inspection with Nordic Inspections. Book on our website or call us today at 701.566.1446 ext. 0
When Is The Best Time To Get Your Home Checked For Radon?
Oct 13, 2026
(0:00) Good morning, 640. It’s the Morning Crew. Doug, Robbie, and our friend Lars Knobloch back in house.(0:05) Good morning, Lars. Hey. Lars, always great to have you in the studio with us. And we have talked (0:11) about radon in the past, but it’s one of those topics where when people are moving or people (0:17) see somebody else having radon checked or a radon mitigation installed, they stop for a second, (0:21) they go, hey, what’s the big deal about radon? Maybe that’s a good place to start, Lars. Explain (0:26) the issues with radon. Yeah, so radon is a naturally occurring gas that comes from the (0:33) breakdown of uranium that we have in our soil. And we have a lot of uranium in our soil. (0:39) And so North Dakota is considered for the EPA Zone 1, which is highest potential for having high (0:47) radon. And we usually, I always been said, I always said, like, based on our tests that we (0:54) have done over the years, the average in we see is between six and seven. Okay. And EPA says that (1:02) 63% of all houses in North Dakota have radon levels above 4.0, which is the action level that (1:11) is set. So when it comes to radon, it’s that gas that you say, and why is North Dakota higher than (1:16) most? Is it minerals in the ground or what? It has to do with the uranium in the soil. That’s (1:21) ultimately where it starts from. Okay. And the breakdown of uranium in.(1:28) That’s interesting to think. Yeah. So radon is the second biggest, second biggest reason for (1:36) lung cancer after smoking. So in non-smokers, you know, it’s the biggest reason for lung cancer. (1:44) EPA puts radon-related lung cancer deaths at about $21,000, not dollars, 21,000 people a year. (1:52) Wow. So when I started doing, you know, radon testing back in 2010, it wasn’t really a thing. (2:03) It wasn’t something that happened a lot in real estate transactions. But now we’re seeing it (2:08) probably up to 50%, but reality is it should be a hundred percent. It’s not mandated? (2:12) It’s not mandated. But the thing is like people think, oh, it’s a new house. This probably won’t (2:19) have any radon. Or, you know, my neighbor tested low, so I’m probably going to be fine. (2:26) My house doesn’t have a basement, so then I don’t need to worry about it. (2:30) It’s more on the area versus what type of house, et cetera.(2:34) Yeah. We have tested high radon in any type of home with full basement, you know, garden level (2:40) basements, slab on grade, crawl spaces, any house can have high radon. But I’d say that (2:46) the deeper you go into ground, the higher the risk, but there’s always a risk.(2:51) Lars Knobloch, Nordic Inspections, joining the KFGO morning crew talking about radon. (2:56) If you had your home tested for radon 15 years ago, 20 years ago, can that number change? Is there (3:02) a need to get it checked? It definitely can change. So one example (3:08) came up recently for us where we, I think we tested a house about two or three years ago and (3:14) the radon was like 3.4. And now this person is selling a house and we tested, we inspected it (3:22) again and tested it for radon also. And it was like six point something. (3:27) Really? Wow. (3:29) So there’s different conditions that plays in for radon. And there’s a lot of variables. (3:35) One is soil conditions where the drier the soil is, the more the soil contracts and it creates (3:42) pathways for radon to enter our houses versus if it’s really wet, then the soil is fully expanded (3:49) and those pathways get kind of sealed up. And then we’ll usually see that radon is lower during (3:56) periods of time like that. And then also we see it higher in the wintertime (4:03) because of the stack effect. Like what’s happening now is that we’re probably starting to close our (4:07) windows. And many think that if you have all your windows closed, radon is just going to build up (4:14) to crazy high levels. But radon has a half-life of 3.8 days. So after 3.8 days, the radon you (4:21) have in your house currently is going to decay into other products. So it doesn’t necessarily (4:26) build up like that, but it’s more like it could be higher as compared to the summer when we have (4:32) our windows open. Makes sense. (4:35) Yeah. So now we don’t have our windows open and we won’t probably moving forward. And that’s where (4:42) it’s a really good time to test your house for radon now. Also because of the stack effect because (4:47) we’re starting heating our houses and hot air is rising and it’s escaping through the building (4:53) envelope into your attic and through the roof. And as that air escapes your house, that new air (4:59) naturally is going to come back in and balance out the pressure. And often that air is pulled (5:05) from the soil. For example, we could sometimes open up the sump plate and we can just feel the (5:11) air coming out of it into the house from the soil, from the drain tile. But so if you have that type (5:18) of positive pressure underneath your house or forcing the air in, then even if you seal up (5:25) your sump pump, you’ll probably, it will probably find its way in elsewhere.(5:29) Okay. So is there ever a point when you test and it’s like X amount and you say, you know what, (5:33) right now I think you’re okay, but we should check again. Kind of like your tires.(5:37) Yeah. (5:38) Right now they’re okay, but you might have another 10,000 miles on them. (5:42) Well, if you go by EPA’s recommendations, they say if it’s between two and four, (5:47) that you should consider taking action. If it’s above four, it’s recommended to take action. (5:52) Okay. All right.(5:53) The World Health Organization recommend to take action at 2.7. (5:56) Oh, wow. (5:58) Thinking of my example, I just brought up from a real story of radon testing in a house with (6:03) two years apart. I think that for me, if you were between two and four, if you want to be truly safe (6:11) and make sure that radon is low consistently, I think putting it in even then, it’s not that (6:18) expensive.(6:19) The mitigation system. (6:20) Yes. (6:20) Okay.(6:21) I mean, you could probably from 1,800 to 2,500 is where most house is going to be at. And then (6:27) there’s some houses with additions and crawl spaces and could be more complex, but that’s kind (6:31) of the cost. (6:33) Does your team also do that? (6:34) We do a lot of radon mitigation systems. We still have some availability this fall, (6:41) but we don’t really like to do them in the winter because it gets really cold and we’re (6:44) gluing pipes and it’s just not a fun job to do out in the really cold weather. (6:49) But you can get it checked now and then get it planned to do next spring. (6:53) Yeah. Or you can get it checked now and we might be able to squeeze. We’re going to (6:56) keep doing it until the weather won’t allow it anymore. (7:00) Is that a long process for you to put that mitigation system in? Is it in my basement (7:04) or where does it? (7:06) So it depends from house to house, but it’s about a half a day for two guys.(7:10) It’s quick. And then it has pretty much instant results where radon is brought down usually (7:16) to zero point something. I’d say no matter how high it is, it can be brought down to (7:24) levels below four, which is what a contractor is required to do. But most of the time it (7:28) ends up zero point something or one point something. (7:31) So there’s still time this fall to have your house tested and mitigated. (7:37) Also from somewhere saying like, oh, well, I lived in the house for 20 years. It’s too (7:42) late now. It’s never too late. (7:45) Like quitting smoking.(7:47) Yeah. (7:47) Right. (7:48) Just do it.(7:48) Yes. (7:49) Yeah. (7:49) Get your radon checked, get the mitigation system in.(7:51) Or I’m going to sell my house in a few years from now. If that’s your plan, still then (7:57) have your house tested for radon because if it is high, it’s likely going to be found (8:03) out when you’re selling your house from the buyer having it tested. (8:07) And then now you’re going to have to put it in anyway. So you might as well do it so (8:10) you can take benefit of it also. (8:12) Right. More buyers are more and more aware of this. So that’s I mean, that could be a (8:16) nice little plus for you. (8:18) Yeah. And from a buyer standpoint, the buyer have buyers have really good cards on their (8:24) hands if radon is tested high at their inspection because they would tell the seller, hey, radon (8:29) came back 12.We want you to fix it. (8:31) The seller says, no, I’m not doing that. (8:33) You know, let’s say the buyers will walk from that.(8:35) Right. (8:36) Then now the seller knows that’s a fact and they have to disclose it to the next buyer. (8:40) So the sellers are often not forced, but you know, pressured pretty hard to take care of (8:48) that problem if it is if that is a problem.(8:50) Yeah. Great stuff. (8:51) Lars Knobloch, Nordic Inspections.(8:53) If someone wants to get their home checked for radon, if they want to have it checked (8:57) for mold, if they’re thinking of buying a home, selling a home, how can they get on (9:01) your project list? (9:02) Give us a call at 701-566-1446. (9:05) Or you can schedule all our services on our website as well. (9:10) Nordiccompaniesinc.com. (9:11) Great stuff.(9:11) Thanks so much, Lars.