How Pros Find Hidden Radon Hotspots: A Real-World EcoTracker Case Study

A radon mitigation system can be running, yet elevated radon can still show up inside a home. For radon professionals, that situation calls for more than checking whether the fan is operating. The bigger questions are: Where and why is radon still entering, and what does the data reveal about the building?

A real-world project from Merritt Gantt of True Air Technologies shows how multi-location radon monitoring helped uncover an unexpected area of elevated radon in a Greenville, South Carolina home. By placing four Ecosense EcoTracker monitors in different areas, the team could compare readings from multiple locations and use those results to guide further investigation.

Watch the EcoTracker Case Study in Action

See how Merritt Gantt of True Air Technologies approached this challenging mitigation project and used multi-location measurements to investigate the problem. 

Project at a Glance 

When an Existing Radon Mitigation System Isn't Enough

The homeowner purchased the Greenville home in 2008. During the original inspection, high radon levels were identified, and a mitigation system was installed. Years later, the homeowner decided to test again and found that radon levels were still higher than expected.

That raised an important diagnostic question: Why wasn't the existing system adequately controlling radon?

Instead of assuming that the answer was simply adding another suction point, True Air Technologies investigated how the existing system was performing and how pressure was communicating beneath the slab.

• Limited Airflow: The investigation found very restrictive soil beneath the slab, making it difficult for the existing suction point to influence the entire area effectively.

• Structural Pathways: The home featured block foundation walls and an attached front porch, structural elements that significantly influence a building's pressure and radon pathways.

Looking Beyond the Obvious

This is where multiple-location measurement became valuable. Rather than relying on a single monitor, the team deployed four EcoTracker units in different areas of the property and compared the readings.

The EcoTracker combines four professional radon detectors, allowing professionals to measure four locations simultaneously. Its Sniff Modes are designed for rapid diagnostics, while the CRM mode handles longer-term monitoring. For a difficult mitigation project, this means a professional can investigate where readings differ rather than treating the entire building as one uniform space.

In this case, one specific location stood out.

The Hidden Radon Hotspot: A Small Front Porch Area

The team identified elevated radon around the home's front porch and band-joist area. The area was relatively small, approximately 3 feet by 4 feet, but the readings indicated that it deserved further attention.

This finding illustrates a crucial point for radon professionals: the physical size of a suspected entry area does not determine its impact. An attached porch, foundation transition, or structural soil connection can heavily influence how radon moves into a home. Instead of guessing where additional suction might be useful, the team had location-specific measurements that directed the exact next steps of the investigation.

Turning Measurements Into a Mitigation Strategy

Once the elevated area was identified, the team incorporated the front porch area into the final mitigation approach:

1. Depressurisation: The porch area was successfully depressurised.

2. System Expansion: Additional suction points were added, bringing the final system to three suction locations (combining the original point with two new ones).

Following the changes, the homeowner continued monitoring radon levels throughout the home. The levels dropped to consistently low levels, with ongoing monitoring showing readings generally around 1–2 pCi/L. The homeowner also moved the Ecosense monitors between the bedroom and office to observe conditions over time.

The true value of this project wasn't just the final number. It was the process used to get there: measure, compare, investigate, modify, and verify.

What This Means for Radon Professionals

Difficult mitigation projects require professionals to look beyond standard assumptions. A few practical lessons from the Greenville case stand out:

• A Running Fan Doesn't Confirm Performance: An operating mitigation fan only tells you that the fan has power. Continuous measurements are required to understand what is happening inside the air.

• Compare Locations, Not Just Numbers: A single reading provides information about just one spot. Simultaneous measurements from multiple areas reveal critical variations that would otherwise be missed.

• Investigate Structural Transitions: Porches, block foundations, and attached structures create micro-environments worth investigating when radon levels don't respond to standard solutions.

• Let Diagnostic Data Guide System Changes: Adding suction points must be based on property conditions and diagnostic data, not on assumptions.

• Continue Monitoring After the Work: Post-mitigation testing confirms whether radon has been successfully reduced. The US Environmental Protection Agency (EPA) recommends testing immediately after mitigation and periodic retesting to ensure levels remain controlled. 

Why EcoTracker Helps With On-Site Diagnostics

The Greenville project demonstrates why having multiple measurement points is crucial during challenging mitigation work, making it a data-driven process rather than guesswork.

The EcoTracker features four simultaneous radon measurements, utilizing 5- and 10-minute Sniff Modes for rapid tracking and a CRM mode for long-term monitoring. Its intuitive mobile app allows professionals to view and compare readings from all four detectors on a single screen.

For professionals investigating unexpected radon issues, this turns a broad question ("Why is radon still high?") into a highly actionable one: "Which specific areas are showing different conditions, and what does that tell us about the building?"

By combining field diagnostics, building knowledge, and location-specific radon data, professionals can eliminate guesswork, make informed decisions, and solve complex mitigation problems with confidence.

Explore how the Ecosense EcoTracker can upgrade your professional radon diagnostics and on-site troubleshooting.

Frequently Asked Questions

1. Can radon levels vary significantly between rooms?

Yes. Radon concentrations can vary drastically between different areas of a building due to variations in pressure, foundation construction, soil contact, ventilation, and specific structural entry pathways.

2. What makes an attached porch worth investigating?

An attached porch foundation creates a unique structural relationship between the building's main foundation, the soil, and the outdoor environment. If radon measurements near this transition are unusually high, it strongly warrants a closer look.

3. How can professionals tell whether an extra suction point is needed?

There is no universal answer. Professionals must use localized diagnostic measurements, pressure-field extension testing (PFE), foundation assessments, and site-specific data to determine if an additional suction point or system adjustment is required.

4. Why use several radon monitors during a diagnostic visit?

Deploying multiple monitors allows professionals to capture and compare environmental conditions at different locations at the exact same time, providing far more diagnostic context than a single snapshot measurement.

5. What should happen after a mitigation system is modified?

The system must be evaluated through immediate post-mitigation testing followed by long-term continuous monitoring. This verifies that radon levels have dropped significantly and remain safely controlled over time.