Where Should a Radon Test Be Placed?

On this page (9 sections)

1. Where should a radon test be placed in a home?
2. Should a radon test go in the basement?
3. Where should I place a test if I don't have a basement?
4. Which rooms are poor places for a radon test?
5. How high should a radon test sit?
6. How should the room be used during a radon test?
7. Which radon test kits fit a home screening?
8. How often should you test radon?
9. What should you do after placing the test?

Place a radon test in the lowest level of your home that you use regularly, in a room where people spend time. Keep it away from drafts, heat, high humidity, and blocked airflow, and follow the test's instructions.

A finished basement family room or bedroom is often a practical choice when it's the lowest lived-in level. If you don't use the basement, choose a regularly occupied room on the main floor instead.

Where should a radon test be placed in a home?

Choose a regularly used room on the home's lowest occupied level. The goal is to measure air in a space where people spend time, under normal conditions.

If you use a basement family room, bedroom, or home office, that room may suit the test. If the basement is only for storage or mechanical equipment, a main-floor living room or bedroom may better fit the usual guidance for a home screening.

Place the device at the height and distance from walls stated in its instructions. Keep it in open air, where furniture, curtains, or stored items won't crowd it.

For a simple overview of the testing process, see How to Test for Radon: The Simple Answer. Placement is one part of a valid test; exposure time and room conditions matter too.

Should a radon test go in the basement?

Use the basement if it's the lowest level you occupy regularly. A finished room where you watch TV, sleep, or work is generally a more useful choice than a space visited only to reach the furnace or store boxes.

Don't put a test in a crawl space, a sump pit, or an unfinished utility area just because it's closest to the ground. Those spots aren't typical living areas and may have conditions that don't match the rooms you use.

If you have a basement, the guide to how to test a basement for radon explains how to choose a testing area and prepare the space. Use the kit instructions if they call for a particular room or setup.

What if the basement is unfinished?

An unfinished basement can still be the lowest level you use regularly, but choose an area that reflects how you use it. If you work out, do laundry, or spend time there, avoid placing the test beside the washer, dryer, or mechanical equipment.

If you rarely enter the basement, use the lowest regularly occupied room instead. Don't choose an unusual spot just to get a higher or lower result.

Where should I place a test if I don't have a basement?

Place it in a main-floor room you use often, such as a living room or bedroom. Pick a stable location that won't be disturbed during the test.

In a home with multiple levels, follow the instructions for the specific test and any local testing guidance. For a test related to a home sale, rental, or other transaction, check whether the program or professional handling it has its own placement rules.

A radon sampling plan can help when you need to test more than one room or compare levels. Don't assume one result describes every floor or room in a large or divided home.

Which rooms are poor places for a radon test?

Avoid rooms with unusual moisture, heat, drafts, or ventilation. Kitchens, bathrooms, laundry rooms, closets, and utility rooms often have conditions that can interfere with a typical home screening.

Keep the test away from:

• Open windows and exterior doors
• Fans, vents, and air-conditioning outlets
• Radiators, fireplaces, and other heat sources
• Direct sunlight
• High-humidity areas, such as bathrooms
• Shelves or corners where airflow is blocked

Follow the device instructions if they name specific distances from walls, doors, windows, or vents. Don't move the test during its exposure period.

How high should a radon test sit?

Use the height specified by the test instructions. Different test types can have different setup rules, so don't rely on a general height if the kit gives a clear measurement.

Set it on a steady surface where it can remain undisturbed. Keep it out of reach of children and pets while leaving the area around it open to room air.

If you need help understanding the kit type and its steps, read What Is a Radon Test Kit? The Short Answer.

The test's instructions take priority over broad placement tips.

How should the room be used during a radon test?

Keep the home and room conditions typical for the test period. Don't change ventilation or daily routines just to influence the reading unless the instructions require a specific setup.

Some short-term tests require closed-house conditions before and during testing. Others may have different rules, so check the instructions for how to handle windows, doors, fans, and heating or cooling systems.

Keep people from bumping, covering, or moving the test. If it is disturbed, check the test instructions or contact the provider for advice before sending it for analysis.

Which radon test kits fit a home screening?

For a home screening, choose a test you can place as directed and return as instructed. We compared these options based on the stated test setup and included analysis details.

First Alert Radon Gas Test Kit

The First Alert kit includes test materials and lab fees, with New Jersey state fees excluded. Results are emailed within 72 hours of lab receipt, and it's recommended for use only in the United States.

Place it in the room you selected before starting the exposure period. Follow the kit's directions for room conditions and how to return the sample.

PRO-LAB Radon Test Kit for Home

The PRO-LAB kit is a short-term test with a 48-hour collection period and lab analysis included. Its instructions describe placement in a frequently occupied room, such as a basement, bedroom, living room, or home office.

Choose a room that matches your normal use of the home, then follow the supplied setup and return directions. Don't place it in a room only because it's convenient if you rarely use that space.

Leaping Lynx Radon Test Kit for Home

The Leaping Lynx kit uses a 48-hour test period and includes lab analysis. Its instructions say to place the detector on the lowest livable level and note that return postage is required.

Use a regularly occupied room on that level, and check the instructions before you begin. The kit is intended for screening, so follow local guidance about next steps if you need a formal measurement.

How often should you test radon?

Retest after major changes to your home or when your earlier test is no longer a good guide. Radon levels can vary, and a result from one time or room doesn't describe every condition.

Use the testing schedule that fits your situation, especially after renovations, changes to the foundation, or work on a radon reduction system. See how often to test for radon for factors that can shape your schedule.

For a longer measurement, use a test designed for that purpose and follow its directions. [What Is a Long Term Radon Test?

The Complete Answer](/what-is-a-long-term-radon-test/) explains how longer testing differs from a short-term screening.

What should you do after placing the test?

Leave the test in place for the full exposure period, then return or read it exactly as instructed. Record the room and date so you can understand what the result represents.

If the result is raised, follow public health guidance on confirmation and next steps. A single screening is useful information, but a professional measurement may be appropriate for a real estate transaction or when you need a more formal assessment.

When deciding where a radon test should be placed, start with the lowest room you use regularly, then avoid drafts, heat, moisture, and blocked airflow. Choose a different room if the first option is mostly storage or mechanical space, and follow the kit instructions from setup through completion.

Frequently asked questions

Where should I place a radon test in a house?

Place it in the lowest level you use regularly, such as a finished basement, family room, or bedroom. Choose a spot where people spend time and follow the test instructions for height, distance from walls, and exposure period.

Keep it away from drafts, direct heat, high humidity, and blocked airflow.

Can I put a radon test in a basement?

Yes, if the basement is the lowest level used regularly. Choose a normal living area rather than an unfinished storage space, utility room, or crawl space.

A test in an unoccupied area may not represent the air in the rooms where you spend time, so use the test instructions and local guidance.

Should I test radon upstairs?

For an initial home screening, test the lowest level that you use regularly. If no basement or lower level is used, that may be the main floor.

Test an upstairs room when you have a specific reason, and follow local guidance or advice from a qualified radon professional.

Where should I not place a radon test?

Avoid kitchens, bathrooms, laundry rooms, closets, crawl spaces, and areas with strong drafts or direct heat unless the test instructions or a qualified professional say otherwise. Don't place it near a window, exterior door, fan, or vent, and don't let furniture or belongings block airflow around it.