CETI Exam Domains 2026: Complete Guide to All 4 Content Areas

How the Four CETI Content Areas Fit Together

The Council-certified Environmental Thermography Investigator credential is built around a practical question: can you use infrared imaging to find real building problems, interpret what the camera shows, and report it credibly? ACAC's application lists four investigation areas where candidates must demonstrate competence:

1. Roof inspections
2. Building exterior investigations
3. Building interior investigations
4. Plumbing investigations

Notice what unites them. Each is a different building system where heat movement reveals something hidden: trapped moisture, missing or compromised insulation, air leakage, or a leaking supply line. The camera is the same across all four, but the thermal behavior of the target changes dramatically. A wet roof membrane at dusk behaves nothing like a leaking pipe behind drywall at midday.

If you are new to the credential itself, our explainers on what CETI certification is and what CETI stands for cover the background. This article focuses on what you actually need to master within each content area.

What the Published Scope Does and Does Not Tell You

This matters because many exam guides invent percentages for each domain. We won't. What can be said honestly is that the same ACAC source also describes thermal and infrared physics together with infrared-camera selection, calibration and operation. So your preparation should cover the four investigation areas and the underlying physics and instrument skills that make those investigations valid.

For a broader view of how demanding the exam is given this uncertainty, see How Hard Is the CETI Exam?, and for the cut score itself, CETI Passing Score 2026.

Domain 1: Roof Inspections

Why timing and conditions dominate roof work

A roof scan is only as good as the thermal conditions during it. Candidates should be able to reason about when a roof has absorbed enough solar energy to create a usable contrast, and when wind, recent rain or cloud cover will degrade or falsify the image. Expect scenario-style thinking: given these conditions and this assembly, what would you expect to see, and what could mislead you?

Confirming what the camera suggests

Infrared shows a surface temperature pattern, not moisture itself. A strong roof-inspection answer recognizes that thermal anomalies are leads to be verified and documented, not conclusions. Report-writing discipline matters here because ACAC's application asks for verifiable investigation reports.

Domain 2: Building Exterior Investigations

Reflections and false positives

Exteriors are where reflective and low-emissivity surfaces cause the most mistakes. Glass, polished metal and glossy finishes can mirror other heat sources, producing patterns that look like defects but are really reflections of the sky, the sun or nearby objects. Candidates should understand emissivity and reflected apparent temperature well enough to explain why a reading may be wrong and how to correct or avoid it.

Inside-outside temperature difference

Envelope investigations depend on a meaningful temperature difference across the building shell. Knowing when that difference is sufficient, and how to document the conditions, is part of producing a defensible exterior investigation.

Domain 3: Building Interior Investigations

Interior findings often point somewhere else

A stain or cool patch on a ceiling is a symptom. The investigator's job is to trace it toward a cause, which may sit in the roof, the exterior wall or a plumbing line. This is why the four content areas overlap in practice, and why candidates who study them as isolated silos tend to struggle with integrated scenarios.

Domain 4: Plumbing Investigations

Why plumbing questions are distinct

Unlike roofs and envelopes, which rely heavily on the sun and ambient conditions, plumbing investigations often depend on the building's own systems. The investigator may need to create contrast deliberately. Candidates should be comfortable reasoning about what to ask the occupant or facility to do, and how to avoid confusing a leak with an ordinary thermal feature of the building.

The Thermography Foundation Under Every Domain

Because ACAC's source also describes thermal/infrared physics and infrared-camera selection, calibration and operation, you should expect the four investigation areas to be tested on top of a shared technical base. Be ready to explain:

• Heat transfer fundamentals: conduction, convection and radiation, and how each shows up in a building thermogram
• Emissivity and reflected apparent temperature: why surface properties change a reading and how operators account for them
• Camera selection and operation: matching a camera's capabilities to the inspection task, and operating it so the data is trustworthy
• Calibration: why an uncalibrated or poorly set instrument undermines every finding
• Image interpretation: scale, span and level choices that can exaggerate or hide an anomaly

Exam Format, Fees and Application Mechanics

Knowing the content is only half the job. The CETI also has an application process that is more involved than simply booking a seat.

How the exam is delivered

ACAC's general examination policy specifies closed-book, computer-delivered multiple-choice testing with at least four answer choices per question. Delivery is through test centers or secure online video proctoring, with Kryterion as the testing provider. Because the questions are multiple choice, success depends on spotting the best interpretation among plausible-looking options, which rewards the diagnostic reasoning described above.

Passing threshold

You need at least 75%, as verified in the current Official CETI Application. For more on what that means in practice, see CETI Passing Score 2026, and for what published data does and doesn't show, CETI Pass Rate 2026.

Fees

A full breakdown is in CETI Certification Cost 2026.

Eligibility and the application package

Candidates need two combined years of relevant science-related postsecondary education and field experience, and ACAC's eligibility FAQ requires at least one actual year of field experience. You provide transcripts when claiming education, and verifiable investigation reports or contracts for relevant investigations, consulting or report writing. The package includes four separate project sheets, the online application and email verifications. No training course is mandatory. Those four project sheets are a natural place to showcase work across your investigation areas, so it helps to think about them alongside your exam preparation. Full details are in CETI Requirements 2026.

Staying certified

Certification is valid for two years. The central renewal procedure calls for 40 RCs, made up of 10 for continued field activity and 30 hours of professional development. However, the credential page instead describes 20 professional-development hours annually. Because these two descriptions differ, confirm the current requirement with ACAC when planning renewal.

Sequencing Your Preparation by Domain

You do not need a generic study system here; you need an order that follows how the content builds. Here is one reasonable progression tied to the four areas:

The physics comes first because every later area depends on it. Roofs come before exteriors because roof thermal behavior is the most intuitive application. Interiors and plumbing close the sequence because they draw on everything earlier. Once you finish a pass, test yourself with the CETI practice tests, then use the CETI study guide and one-page cheat sheet for consolidation.

Where the Credential Gets Used

The four content areas map directly to the kinds of work where thermography adds value: building and roof assessment, moisture and water-intrusion investigation, envelope and energy-related diagnostics, and leak tracing. That points to building consultants, inspection and forensic-investigation practices, and facility or property-management teams as natural users of the credential. We avoid quoting any hiring figures or pay ranges here because none are supported by ACAC's published materials; for what is and isn't known, see CETI jobs, the CETI salary guide, and whether the certification is worth it.

One honest context point: ACAC's December 31, 2025 activity report lists 3 current CETI certifications. That is a count of holders, not exam volume, but it signals a small, specialized credential community. For some professionals that scarcity is part of the appeal; for others it is a reason to weigh the credential carefully against their market.

Frequently Asked Questions