- What the Four Domains Actually Represent
- Domain 1: Roof Inspections
- Domain 2: Building Exterior Investigations
- Domain 3: Building Interior Investigations
- Domain 4: Plumbing Investigations
- The Thread Under Every Domain: Infrared Physics and Camera Operation
- Exam Format, Fees and Application Mechanics
- Sequencing the Four Domains in Your Prep
- Where Domain Knowledge Gets Used
- Frequently Asked Questions
- The CETC is issued by the American Council for Accredited Certification (ACAC) and is CESB-accredited.
- Four competency areas: roof, building exterior, building interior and plumbing investigations. ACAC publishes no official weighting.
- Infrared physics and camera selection, calibration and operation underpin every domain.
- Passing requires at least 75%; initial cost is $500 for US/Canada applicants.
What the Four Domains Actually Represent
The Council-certified Environmental Thermography Consultant (CETC) credential is awarded by the American Council for Accredited Certification (ACAC), and its content is organized around four investigation areas: roof inspections, building exterior investigations, building interior investigations and plumbing investigations. These headings reproduce the competencies ACAC lists for its application. They are not a published exam blueprint with percentage weights, and ACAC has not announced an official total domain count beyond what its competency page describes.
The same ACAC source also describes thermal and infrared physics, along with infrared-camera selection, calibration and operation. In practice, that means the exam is not purely a "where do I find the leak" test. You are expected to understand why a camera shows what it shows, and when its output can mislead you. For a broader orientation, see What Is CETC Certification? and the deeper difficulty guide.
Domain 1: Roof Inspections
Roofs are the classic thermography application because solar loading and nighttime cooling create strong, readable temperature differences. Wet insulation holds heat differently than dry insulation, and that contrast is the core of many roof surveys.
Roof Inspections: What to Master
Candidates should be able to explain how roof moisture appears on a thermogram, why timing matters, and how to separate real anomalies from surface artifacts.
- Why roof surveys are typically timed around thermal transitions such as after sunset, when stored solar heat releases unevenly from wet and dry areas
- How roof assembly type (membrane, insulation layers, deck) changes what an anomaly looks like
- How weather conditions, wind, cloud cover and recent precipitation affect data quality
- How to document findings so a client can locate suspect areas on the actual roof
Typical Pitfalls in Roof Questions
Expect scenario-style reasoning rather than rote definitions. A question might describe conditions at the time of the scan and ask whether the resulting image is trustworthy. Surface reflections, standing water, ballast, patches and mechanical equipment can all produce thermal patterns that are not moisture. Your job is to know which variables you must rule out before calling an area suspect.
Domain 2: Building Exterior Investigations
Exterior work covers the building envelope as seen from outside: walls, cladding, windows, doors and the junctions between them. Here the physics of heat transfer, specifically conduction, convection and radiation, does the heavy lifting.
Building Exterior: What to Master
The emphasis is on reading envelope performance and moisture intrusion through the skin of the building.
- How temperature differential between inside and outside affects exterior image quality
- How air leakage and thermal bridging present at wall penetrations, framing lines and transitions
- How different cladding materials emit and reflect infrared energy differently
- Why sun exposure, wind and rain history can hide or imitate genuine defects
- How to choose viewing angles that limit reflected apparent temperature errors
Emissivity and reflected apparent temperature are the recurring trouble spots here. Glass, polished metal and painted surfaces behave very differently from masonry or wood, and a candidate who treats every surface as the same will misread the data. Practice explaining, in plain language, why a shiny surface can look "cold" without actually being cold.
Domain 3: Building Interior Investigations
Interior investigations are where thermography meets occupied space, and where moisture, air movement and missing insulation are most often the client's concern. Unlike roof work, interior scans give you more control over conditions, but they demand careful interpretation.
Building Interior: What to Master
Know how to read interior surface temperatures and what they imply about what is behind the finish.
- How to detect suspected moisture in walls, ceilings and floors without confusing it with ordinary thermal patterns
- How insulation voids, settled insulation and air leakage paths show up on interior surfaces
- How HVAC operation, sunlight through windows and recent occupant activity alter surface temperatures
- Why a thermal anomaly is a prompt for verification, not a diagnosis on its own
A recurring principle across the credential is that a thermogram indicates a temperature pattern, not a proven cause. Interior questions often test whether you know when to recommend confirming with another method rather than reporting a conclusion the image cannot support. If you are mapping the full credential path, CETC Requirements explains how that investigative experience factors into eligibility.
Domain 4: Plumbing Investigations
Plumbing investigations apply thermography to supply lines, drain lines and the leaks and failures associated with them. Water at a different temperature from its surroundings creates a detectable signature, but only if conditions cooperate.
Plumbing Investigations: What to Master
The key skill is linking a thermal signature to a plausible plumbing cause while respecting what the camera cannot see.
- How hot and cold supply lines present, and how radiant heating or hidden lines can look similar to leaks
- How a leaking line can cool or warm surrounding materials over time
- Why flow state, line material and burial or concealment depth limit detection
- How to distinguish a leak from condensation, insulation gaps or unrelated heat sources
Because plumbing findings often involve concealed conditions, expect questions about the limits of the method. Knowing when thermography is the wrong tool, or only a partial one, is part of professional judgment and is fair game on a consultant-level exam.
The Thread Under Every Domain: Infrared Physics and Camera Operation
Each of the four domains rests on the same technical base that ACAC describes: thermal and infrared physics, plus infrared-camera selection, calibration and operation. A candidate who studies the domains as isolated application areas will struggle, because the hard questions usually combine a field scenario with a physics concept.
| Concept | Why It Matters Across Domains |
|---|---|
| Emissivity | Determines how accurately surface temperature can be read on roofs, siding, glass and finishes |
| Reflected apparent temperature | Causes false hot and cold spots on shiny or glazed surfaces, especially on exteriors |
| Heat transfer modes | Explains conduction through assemblies, convection from air leakage and radiation from sun-loaded surfaces |
| Camera calibration and settings | Affects measurement credibility and whether results can be defended in a report |
| Thermal contrast and timing | Governs whether a moisture or leak anomaly is visible at all on a given day |
For a compact refresher on these ideas, the CETC cheat sheet is a handy companion, and the full study guide shows how to fold physics review into your domain work.
Exam Format, Fees and Application Mechanics
Knowing the domains is only half the picture. The CETC process has specific mechanics worth understanding before you start.
Question Style and Delivery
ACAC's general examination policy specifies closed-book, computer-delivered multiple-choice testing with at least four answer choices per question. Testing is delivered through Kryterion, either at a test center or through secure online video proctoring. The passing threshold is at least 75%, as verified in the current Official CETC Application. See CETC Passing Score for more on how to think about that target.
Eligibility and the Application Package
Eligibility is built on eight combined years of relevant science-related postsecondary education and field experience, subject to ACAC's education-credit assessment. Its eligibility FAQ requires at least one actual year of field experience regardless of college credits. The application package includes:
- Transcripts when you claim education toward the eight years
- Verifiable investigation reports or contracts showing relevant investigations, consulting or report writing
- Four separate project sheets
- The online application and email verifications
No training course is mandatory. You must complete the application process, including the examination, within six months, and certification requires unanimous board approval. Details on timing are in CETC Exam Dates.
| Item | Amount (USD) |
|---|---|
| Examination fee | $100 |
| Certification fee | $400 |
| Initial total, US/Canada applicants | $500 |
| Applicants outside US/Canada (per official application) | $525 |
| Retake | $100 |
| Renewal | $400 |
Sequencing the Four Domains in Your Prep
Since the domains share a physics foundation, the most effective order starts there and then moves from the simplest scanning conditions to the most inference-heavy ones. Treat this as a CETC-specific sequence, not a generic schedule.
Physics and Camera Operation
- Emissivity, reflected apparent temperature, heat transfer modes
- Camera selection, calibration and settings
Roof Inspections
- Moisture signatures, timing and weather limits
- Separating real anomalies from surface artifacts
Building Exterior, then Interior
- Envelope performance, air leakage, thermal bridging
- Interior moisture and insulation patterns
Plumbing, then Mixed Practice
- Leak signatures versus look-alikes
- Timed multiple-choice sets across all four domains
Roof comes before exterior and interior because its conditions are the most intuitive, and plumbing comes last because it leans hardest on the "anomaly versus cause" judgment that the other domains build. When you reach the mixed-practice stage, use the practice test to expose which domain still produces missed questions. Our study guide covers the broader approach to first-attempt success.
Key Takeaway
Do not study the four domains as separate silos. Every roof, exterior, interior and plumbing question can hinge on the same physics concepts, so a weak spot in emissivity or reflected temperature will cost you points in all four areas.
Where Domain Knowledge Gets Used
The four domains map to work that building professionals, consultants and investigators perform: documenting roof conditions, assessing envelope performance, tracing interior moisture and locating plumbing problems. The credential's eligibility rules reflect this, since applicants must show verifiable investigation reports, consulting or report writing rather than classroom learning alone. For the career side, see CETC Jobs, CETC Salary Guide and Is the CETC Certification Worth It?. We deliberately avoid quoting earnings or hiring statistics here, since none are supplied by ACAC. One fact worth noting: ACAC's December 31, 2025 activity report lists 10 current CETC certifications, which is a count of holders and not a measure of exam volume or pass rates. For more on results data, see CETC Pass Rate.
Frequently Asked Questions
The four supplied competency areas are roof inspections, building exterior investigations, building interior investigations and plumbing investigations. ACAC has not published an official total domain count or weighting, so treat these four as the known scope rather than a complete blueprint.
The source material lists them without weights. Prepare for all four, and be cautious about any outside claim of exact percentages until ACAC provides a full blueprint.
The threshold is at least 75%, as verified in the current Official CETC Application. The exam is closed-book, computer-delivered multiple choice with at least four answer choices.
ACAC's competency page also describes thermal and infrared physics and infrared-camera selection, calibration and operation. These concepts underpin every domain, so study them alongside the four investigation areas.
No mandatory training course is required. You do need to meet the eligibility standard of eight combined years of education and experience, including at least one actual year of field experience, and complete the application and examination within six months. See CETC Requirements for the full picture.