Free Ohio radon test kit: how to use it in a Columbus home

A free radon kit is on its way to your mailbox, or you are about to order one, and you want the number it produces to be worth acting on. The device is the easy part. The house, the spot and the timing decide whether the result means anything, so here is the whole routine in order.

Getting the kit

Step 1. Order it through ohio.radon.com

The Ohio Department of Health sends homeowners to ohio.radon.com for free test kits, and the Delaware Public Health District points Delaware County residents to the same site. Order it for the house you own or rent and live in. Ohio law lets an owner or lessee test their own building without a radon license, so a homeowner kit is fully legal for your own home. The licensing requirement in ORC 3723.02 applies when someone tests a building for somebody else.

If you would rather not wait for the mail, a hardware-store charcoal kit costs $15 to $30 and the placement rules below apply to it just the same.

Step 2. Read the instructions before you open anything

Kits differ in how long they stay out, what you record, and how fast they need to reach the lab. Where this guide and the printed sheet in the box disagree on exposure time or mailing, the sheet wins. Before starting, find the spots where you will write the start date and time, the stop date and time, and the room.

Choosing the spot

Step 3. Go to the lowest level someone could live on

Ohio's radon measurement protocol, the rulebook licensed testers work from, is also the best placement guide a homeowner has. It puts the device on the lowest structural level suitable for occupancy, in a room that could be used regularly. In a 1920s Clintonville house or a period-revival Bexley home with a full basement, that means the basement, as long as it has a room a person could reasonably use.

Several rooms are off the list because the protocol says results from them cannot support a decision: bathrooms, kitchens, laundry rooms, closets, crawl spaces and sump pits. A split-level needs one device in each foundation area (the basement, a room over the crawl space, the slab-on-grade room), and a large tested level gets one more device for every additional 2,000 square feet.

Step 4. Measure the distances

Take a tape measure downstairs. The device should sit:

• at least 3 feet from doors, from windows that open to the outside, and from vents
• at least 1 foot from any exterior wall
• between 20 inches and 6 feet above the floor
• at least 4 feet from the furnace, a space heater or any other heat source
• at least 10 feet from a sump pit
• out of direct sunlight

A small table or shelf near the middle of a basement room usually clears every one of those distances at once. Leave the kit there for the whole test and let the household know not to move it.

Setting up the house

Step 5. Close the house 12 hours ahead

For any test shorter than 96 hours, Ohio's protocol has closed-house conditions begin at least 12 hours before the device opens, and they hold until it is sealed. In a Central Ohio house that means:

• every window shut, upstairs included
• exterior doors kept closed apart from normal coming and going
• the furnace or central air left running as it normally would
• the whole-house fan off, and the fireplace cold unless it is the main heat source
• no ceiling fan, humidifier, dehumidifier, air cleaner or window air conditioner running within 20 feet of the kit

A house aired out the morning of the test tends to read low, and a low number is exactly the kind people trust without question. Plan the test for days when the house would be closed anyway, which in Columbus means the heating season is the easiest time to get it right.

Step 6. Check the forecast before you start

The protocol does not allow a test shorter than 96 hours to run through severe storms or steady winds of 30 mph or higher, because wind pushing on one side of a house changes the pressure inside it. Look at the forecast for the full test window. If a strong front is coming through, start a few days later.

Finishing the test and reading the number

Step 7. Seal it and mail it promptly

When the exposure time on the instructions is up, close the kit exactly as shown, fill in the stop date and time, and get it into the mail the same day if you can. The instructions set a mailing window for a reason, and a kit that sits in a drawer for a week can miss it and come back unusable. Mailing is part of the test, not an errand for later.

Step 8. Match the result to a next move

For a house that is not being sold, Ohio's protocol sets out a simple follow-up path:

• below 4 pCi/L, nothing further is required; test again in two years or after a remodel
• from 4 up to 8, run a second short-term test in the identical spot, or a long-term test that captures the average across the seasons
• 8 or above, run a second short-term test soon, then base the decision on the two results together

The test result FAQ explains the units and what counts as high, and for anything between 2 and 8 our borderline result guide walks through the decision band by band.

When a homeowner kit is the wrong tool

A kit answers one question well: roughly what is the radon level in my own house right now? It is the wrong tool for three jobs.

If a home is being bought or sold, the test belongs with an Ohio-licensed radon tester, not a mailed kit. The protocol for a transaction runs at least 48 hours with either two side-by-side devices or a continuous monitor, and it comes with a signed noninterference agreement and a notice posted at every entry. A buyer testing a seller's house is testing someone else's building, which is where the license requirement applies.

The second job is post-mitigation verification. Ohio's mitigation standards call for that first test to be run by the specialist who installed the system or by an independent licensed tester. The third is settling a disagreement: when a homeowner kit and a professional test land on opposite sides of 4, the licensed report documents its placement, timing and conditions, which makes it the stronger basis for a decision.

For everything else, a kit is a sound first look. The DIY testing FAQ covers the tradeoffs, and when you need a report that holds up in a sale or after an install, see professional radon testing or call or text us to set a date.