Radon testing questions for a beginner

I am a new home inspector looking to add Radon. Have a couple questions. Is testing with a single charcoal canister appropriate testing for the roughly $140 I’ll charge for the test? EPA recommends 2, but is what they recommend always what people are actually doing? And likely I’ll be setting the canister the day of the inspection but I’ll be opening and closing doors, negating the 12 hour rest period required prior. Can I leave the canister an extra 12 hours or do I just need to make separate arrangements for placing the canister when the time is appropriate?

Radon testing for RE Transactions, using charcoal canisters, requires two canisters placed side by side, (4 inches apart), to insure as accurate a reading as possible given the short term test duration.

Whenever possible, attempt to place the test prior to the inspection so it is complete at the inspection comence time. If there is any question as to the “closed home condition” for the 12 hour period, extend the test duration for the full 12 hours.

Remember, the test duration is required as a MINIMUM of 48 hours with a MAXIMUM of 96 hours. Most inspectors seem to have it in their heads that 48 hours is the requred duration. WRONG!!

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Thanks Jeff,
I’ll be sure to use 2 canisters. And regarding placement time, then it is ok to place during the inspection and just wait a minimum of 60 hours.

Yes, but be cognizant of the needs for the Radon test while inspecting, and minimize the duration of open times while testing doors, windows, exhaust fans, etc. Be sure to discuss this with all parties present during the inspection.

My recommendation for Radon canisters… https://rtca.com/product.asp?prodID=10&catID=1
Note: the website shows Consumer Pricing ONLY until you sign up as a business on their site. Your true cost is basically 50% of List. Also note: their canisters can run for a total of 168 hours (7 days)!!

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Where are you located? Canisters don’t work in my area for Real Estate transactions. Only monitors. With those you usually only need one, for every foundation type.

That’s highly unusual as most CRM’s are calibrated and QC’ed using canisters!!
Now, many generalize those POS “sponges” you hang from the joists with Canisters, and no, they are not the same! If you look at the State requirement for testing devices, “Professional Canisters” such as I linked to above, meet the required standards, whereas those crappy sponges DO NOT!

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Before you start charging someone $140 for a service that they can do themselves for free, I suggest that you take INTERNACHI’s free Radon Inspections Course and learn the protocols and science behind radon testing so that you can earn that $140 fee and ensure that your results are as accurate as possible, given the constraints of the duration allotted for a Real Estate transaction. I assume that you have no education on how to do a radon test because you asked a basic question. (I’m sorry if i’m wrong about that) The class is 16 hours. Happy reading.

Short answer to your question is that you can go ahead and start the radon test. You don’t have to come back later.

“Closed-building conditions require keeping all windows closed, keeping doors closed except for normal entry and exit, and not operating fans or other machines that bring in air from outside. Note that fans that are part of a radon-reduction system, or small exhaust fans operating for only short periods of time, may run during the test.”

If you are just opening and shutting windows to test function, not leaving them open, then that is ok. Small fans such as bathroom ventilation and range hoods are run for a very short time for testing. That is OK also. Whole house fans are not OK.

Good luck with your studies, and welcome to the forum.


I took the Radon test but these questions linger. Yes, I am new. But the course only states the available methods, but not the most common, or easiest. I am in Colorado. I would prefer the charcoal canisters over some expensive machinery but I do want to give value. If I can do simple window operations and still provide a test at the same time that would be ideal. I just want further clarification and different points of view than what the course states.

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You are on the right track, Jeremy. You are learning and this will make you a great inspector. Some guys don’t follow protocol (don’t know protocol) and don’t care. Remember your clearances to floor, ceiling, walls, doors/windows etc when choosing where to place the canisters. You will do fine.

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Ditch the canisters and invest in a monitor. Canisters take the same amount of time in the home as a monitor BUT require extra time to send out to the lab and not to mention the cost of the canister. $20 for 2 RTCA canisters which includes the lab analysis add $8.50 2 day priority mail. The cost and time adds up. The last thing you want the agent doing is hiring someone else to do the radon test it might be your competition. When it comes to real estate sales time is KING. So as someone mentioned a great idea is to set the test early and pick it up when you do the inspection then both reports are delivered at the same time. BAMB! FYI keep a few canisters on hand in case your monitor(s) are busy or you don’t feel comfortable leaving your expensive monitor in a home.

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So, does the OP have the business to support the purchase of CRM(s)??
MANY new inspectors make that exact mistake.
DO NOT put out the cash you may need for operations until you have made the determination as to the actual NEED!
IMO, go one year with Canisters, then make the switch if business warrants it.
Think I’m wrong? Just view this MB and Ebay for all of the USED CRM’s for sale that are new/hardly used… and also note the long list of FAILED new inspectors selling their new tools off trying to recoup their losses!!


Recommendations for a CRM?

<Recommendations for a CRM?>

NRSB approved devices

If you’re new at this, I suggest the lease program with Radalink. They do your Quality Assurance, and guide you to having reliable test results.

Welcome to the forum Peter. :+1:

Hello to all.
I am new regarding the Radon testing an i have a couple of basic questions.
I finished with the Radon class (certification ) from NACHI and i am wondering if i am allowed to but a CRM and do the Radon testing by my self?
If yes, then who will write the report that the Real Estate agent want for their contracts?
I would gratefully appreciate any fast response! i am loosing inspections only for the Radon testing since the most of the agents want both (home inspection and Radon testing)

The answer to your first question depends greatly on what state your in. You may also want to check with your insurance carrier to make you’re covered for this type of service.

As for the report, whoever does the radon testing is responsible for producing the report.

While it may stink to lose business because of a service you don’t yet provide, take your time and make sure you know what you’re doing, you’re doing it correctly and you’re doing it legally first.


Mr. Young,
I really appreciate your fast response and i am very grateful for!
I will check the requirements in my state though I leave in Maryland (in case that you might know something about this State) and of course i will agree with you regarding the legal procedures and this one of the reasons i am trying to figure out what actually is the right way to do it.

Can you just set the test at the end of the inspection?? That way you don’t need to worry about breaching the protocol.

The inspection process breaches the closed house protocol, IMO. Whenever possible, I would set the test 60+ hours prior to the inspection so it was completed at the start of the inspection, and no breach was created from my inspection process.

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Btw… (Yesterdays inspection) a common problem I often see with CRMs from ‘other’ inspectors tests I come across…


Tell me again how superior CRMs are to Lab analyzed canisters?!?!