Radon testing is a professional measurement of radon gas levels inside a home to determine whether the concentration exceeds the EPA's action level of 4.0 pCi/L. Radon is a naturally occurring, colorless, odorless radioactive gas that seeps into homes through foundation cracks and gaps — and the EPA identifies it as the second leading cause of lung cancer in the United States, responsible for an estimated 21,000 deaths per year.
Insight Home Inspection Services, LLC provides professional radon testing for homes in Nashville, Knoxville, and Chattanooga, Tennessee. Founded in 2014, Insight has completed over 5,000 inspections across Middle and East Tennessee.
Why Radon Testing Matters in Tennessee
Tennessee has elevated radon risk. The EPA divides counties into three zones based on predicted average indoor radon levels. East Tennessee — including Knoxville and the surrounding counties — falls in Zone 1, the highest-risk category, where predicted average indoor radon levels exceed 4.0 pCi/L. Middle Tennessee — including Nashville and Chattanooga — falls in Zone 2, with predicted levels between 2.0 and 4.0 pCi/L.
The EPA recommends that all homes be tested for radon, regardless of geographic zone. Radon levels vary from house to house. A home with low radon can sit next to a home with dangerously high levels. The only way to know is to test.
The EPA Action Level
The EPA has set an action level of 4.0 picocuries per liter (pCi/L). If a test result meets or exceeds 4.0 pCi/L, the EPA recommends installing a radon mitigation system. The World Health Organization recommends action at 2.7 pCi/L. There is no known safe level of radon exposure.
How Radon Testing Works
Insight Home Inspection Services uses a continuous radon monitor (CRM) — a professional-grade electronic device that measures radon concentrations hourly over a minimum 48-hour testing period.
The process:
1. Placement — The CRM is placed in the lowest livable level of the home, typically the basement or ground-floor living area. It is positioned away from exterior walls, windows, and doors.
2. Closed-building conditions — Windows and exterior doors must remain closed for at least 12 hours before the test begins and throughout the entire testing period. Normal entry and exit through doors is permitted.
3. 48-hour minimum test — The monitor collects hourly readings for a minimum of 48 hours, as required by EPA testing protocols.
4. Data retrieval — An Insight inspector retrieves the monitor and downloads the data. The hourly readings are reviewed for consistency and any evidence of tampering or interference.
5. Results — Radon test results are included in your inspection report, delivered within 24 hours.
A continuous radon monitor provides more reliable data than charcoal canisters because it records hourly fluctuations and includes tamper-detection features.
What Happens If Radon Levels Are High
If test results are at or above 4.0 pCi/L, radon mitigation is recommended. Mitigation typically involves installing a sub-slab depressurization system — a vent pipe and fan that draws radon from beneath the foundation and vents it above the roofline. A qualified radon mitigation contractor installs the system. Mitigation costs typically range from $800 to $1,500 for most homes.
After mitigation, a follow-up radon test confirms that levels have been reduced. Radon mitigation systems are highly effective and can reduce levels by up to 99%.
During a real estate transaction, elevated radon is a negotiable item. Buyers commonly request that the seller install a mitigation system or credit the cost at closing.
Radon Testing Cost
Radon testing is available as a $200 add-on to any Insight home inspection. It can be scheduled alongside your standard home inspection in Nashville, Knoxville, or Chattanooga. Insight's standard home inspections range from $450 to $1,000+ depending on square footage, with 400+ items inspected and reports delivered within 24 hours.
Frequently Asked Questions
How long does a radon test take?
A radon test requires a minimum of 48 hours. The continuous radon monitor is placed during the inspection and retrieved two days later. Results are included in your inspection report.
Can I do a radon test myself?
DIY charcoal test kits are available at hardware stores, but they are less accurate than professional continuous radon monitors. Lenders and real estate transactions typically require professional testing.
Does every home in Tennessee need radon testing?
The EPA recommends testing every home, regardless of location. East Tennessee (Knoxville area) is in the highest-risk Zone 1. Middle Tennessee (Nashville, Chattanooga area) is in Zone 2. Both zones have homes that test above the 4.0 pCi/L action level.
Can radon levels change over time?
Yes. Radon levels fluctuate seasonally and can change due to home renovations, foundation settling, or changes in ventilation. The EPA recommends retesting every two years, and after any major structural changes.
Does a new home need radon testing?
Yes. New construction is not immune to radon. Even homes built with radon-resistant features should be tested to verify that levels are below the action level.
Will high radon kill a real estate deal?
Rarely. Radon mitigation is straightforward and cost-effective. Most buyers and sellers negotiate a mitigation installation or closing credit rather than walking away from the transaction.
Schedule Radon Testing Today
Contact Insight Home Inspection Services to add radon testing to your upcoming inspection in Nashville, Knoxville, or Chattanooga.
- Nashville: (615) 436-0606
- Knoxville: (865) 274-0808
- Chattanooga: (423) 395-2020
- Email: info@inspectedbyinsight.com