What it is and how it works
The sensor, the sampling and the readings
A long-term test answers a different question from a short-term one. PRO-LAB says the RL116 gives an average radon level in your home over an extended period, 3 months to 1 year. The EPA counts any test that stays in a home for more than 90 days as long-term, and says a long-term test is more likely than a short-term test to tell you a home's year-round average, because radon levels tend to vary from day to day and season to season.
The detector is passive. PRO-LAB describes a black detector sealed in a clear bag: as soon as you open the bag, the detector is on and the test has begun. Nothing runs on power and nothing shows a number. The measurement happens at the end, when the laboratory analyzes the detector you mail back with its data card.
PRO-LAB's page does not name the technology inside the detector. The EPA says alpha track and electret ion chamber detectors are the devices commonly used for long-term testing. Because PRO-LAB does not say which one the RL116 uses, we do not either; the practical steps are the same for you whichever it is.
PRO-LAB positions the RL116 as the follow-up to its short-term kit. It describes short-term detectors such as its model RA100 as excellent for initial screening, and recommends the RL116 for more conclusive results when a first short-term result calls for a long-term follow-up. That matches the EPA's sequence: when a first short-term result is at or above 4 pCi/L, take a follow-up test, either a long-term test or a second short-term test, and the long-term test is the one more likely to show the year-round average.
PRO-LAB says its test kits are sold at more than 40,000 stores, naming The Home Depot, Lowe's, Menards, Ace Hardware, True Value, Kroger and CVS among them, and that you can call PRO-LAB to buy one if you cannot find it. Which stores stock the long-term kit on a given day is not something PRO-LAB's page states.
Independent evidence
Who checks a device like this
C-NRPP's consumer evaluation covers electronic monitors, not laboratory-analyzed test kits, so it has no result for PRO-LAB RL116. A kit's result comes from the laboratory that analyzes it; where the maker names that laboratory, “What it is and how it works” above says so.
What the manufacturer says
PRO-LAB's own statements, attributed
- PRO-LAB saysPRO-LAB states that the RL116 gives an average radon level in your home over an extended period of 3 months to 1 year.
- PRO-LAB saysPRO-LAB states that it sends an easy-to-read evaluation of your home's radon level within 2 weeks of receiving the detector.
- PRO-LAB saysPRO-LAB states that it recommends the RL116 for more conclusive results when a short-term result calls for a long-term follow-up.
- PRO-LAB saysPRO-LAB states that New Jersey residents pay an additional fee for the New Jersey Department of Environmental Protection's administrative costs.
These are PRO-LAB's own statements, attributed to it. They are not our findings, and we have not tested this product ourselves.
Who it fits
Good fit if, and look elsewhere if
Good fit if
- You want a home's average over a season or a year rather than a few days.
- A short-term test came back at or above 4 pCi/L and you want the long-term follow-up the EPA describes.
- You can leave one detector undisturbed for at least three months.
- You want a laboratory result without buying an electronic monitor.
Look elsewhere if
- You need a result within days, for example during a home sale.
- You want to watch radon change hour by hour or week by week; this kit reports one average at the end.
- You are likely to move or disturb the detector before three months are up.
- You want the lab fee confirmed in the kit price; PRO-LAB's long-term page does not state it.
Setup and placement
4 steps
- PRO-LAB's instructions, following the EPA, put the test in the lowest lived-in area of the home that is regularly used for 8 to 10 hours a day, in a room where the detector is not exposed to drafts from vents, doors or windows. They rule out a kitchen, bathroom, crawl space, furnace room, closet or laundry room, and any spot in direct sunlight or near a heat source such as a fireplace or heater.
- Open the bag only when you are ready, because the test begins the moment you do. Hang or place the detector at least three feet from exterior doors or windows and at least two feet off the floor, then leave it in place and undisturbed for three to twelve months.
- Record the detector's serial number, the test location and the start date on the long-term data card, then detach the card and keep it somewhere safe: PRO-LAB says you need it to complete the test. When the test ends, add the end date and the rest of the details, since a card with missing information means the detector cannot be analyzed.
- The EPA's general guidance points the same way: the lowest lived-in level, a room used regularly but not the kitchen or bathroom, at least 20 inches above the floor and away from drafts, high heat, high humidity and exterior walls.
For where any radon test or monitor should sit in a home, see where to place a radon test.
What is in the box, and what it costs to run
Contents, warranty and running costs
In the box
PRO-LAB's instructions describe the kit's parts: the detector in its clear bag, a long-term radon data card with a detachable part to keep, and an enclosed Business Reply envelope with prepaid postage for the return. Questions go to PRO-LAB by phone.
Running costs
Return postage is prepaid. PRO-LAB's long-term page does not say whether a lab fee is due with the detector, as its short-term page does for the RA100, so check the current terms before you buy. New Jersey residents send an additional state fee with the detector. There are no batteries, apps or subscriptions; the cost is one kit per test.
Questions people ask
6 questions, answered
How long does the PRO-LAB long-term radon test take?
PRO-LAB says to leave the detector in place for three to twelve months. After you mail it back within 24 hours of the end of the test, PRO-LAB says it sends the evaluation within 2 weeks of receiving it.
When does the test start?
As soon as you open the clear bag. PRO-LAB says the detector is on from that moment, so open it only when it is in place and you have the data card ready.
Should I use a long-term or a short-term test?
A short-term test is the quickest way to screen a home. A long-term test, more than 90 days, is more likely to tell you the year-round average. The EPA suggests a follow-up when a first short-term result is at or above 4 pCi/L, and a long-term test is one of its two options. [Short-term vs long-term](/radon-test-kits/short-term-vs-long-term/) sets the choice out side by side.
Where should I put the detector?
In the lowest lived-in area used for 8 to 10 hours a day, at least two feet off the floor and three feet from exterior doors and windows, out of drafts, sunlight and heat. Not in a kitchen, bathroom, crawl space, furnace room, closet or laundry room.
What if I lose the data card?
PRO-LAB says the card is needed to complete the test, and that a detector sent with missing information cannot be analyzed. Keep the detached card somewhere safe for the months the test runs.
Is the PRO-LAB RL116 sold at Home Depot or Lowe's?
PRO-LAB names The Home Depot, Lowe's and Menards among the stores that carry its test kits, and gives a phone number to buy direct if you cannot find one. It does not list which stores stock the long-term kit at any moment.
What to do next
- See every long-term test kit we coverEach with the same fields and its evidence.Go
- Place it where it countsThe lowest lived-in level, away from drafts, at least 20 inches up.Go
- Read your resultWhat a number in pCi/L means and what the EPA says to do next.Go
- Testing for a home sale?Find radon measurement professionals in our directory.Go