- Which CIE This Cheat Sheet Covers
- The Exam at a Glance
- The Seven Official Domains in One Pass
- The Five-Book Reference Shelf
- Eligibility and Application in 60 Seconds
- Money, Terms and Renewal
- Exam-Day Logistics
- Numbers You Can Quote (and Ones You Shouldn't)
- Sequencing the Domains in a Study Plan
- Who Uses the Credential
- Frequently Asked Questions
- The exam is 100 multiple-choice questions in three hours, closed book, with a 75% passing score.
- Seven official domains exist, but ACAC publishes no percentage weights, so never trust anyone's claimed domain allocation.
- Initial cost is $500 for a two-year term: $100 exam plus $400 certification; retakes are $100.
- Four project sheets plus documented indoor-air-quality field experience are required before certification is granted.
Which CIE This Cheat Sheet Covers
Several credentials share the letters "CIE." This page covers only the Council-certified Indoor Environmentalist, issued by the American Council for Accredited Certification (ACAC) through its CIE Certification Board. The program is accredited by the Council for Engineering and Scientific Specialty Boards (CESB). If you are looking for an overview of the credential itself before drilling into facts, start with What Is CIE Certification? or What Does CIE Stand For?, then come back here for the one-page review.
Everything below is drawn from ACAC's published materials: the official exam-domain chart approved February 7, 2024, the CIE Candidate Handbook, and ACAC's fee, application, exam and recertification pages. Where those sources disagree with each other, this sheet says so rather than picking a winner silently.
The Exam at a Glance
| Item | What ACAC Publishes |
|---|---|
| Question count | 100 multiple-choice questions |
| Answer options | At least four per question |
| Time allowed | Three hours |
| Format | Computer-delivered, closed book |
| Passing score | 75%, set by the CIE Certification Board using the Modified Angoff method |
| Test provider | Kryterion, Inc.; testing center or online video proctoring scheduled through ACAC |
| Practical component | None described |
| Scored vs. unscored items | Not published |
| Results | Handbook describes electronic grading, immediate scores and an email confirmation |
The handbook describes a common question set with randomized question and answer order, and adaptive testing is not described. Calculator permission is not verified in the materials reviewed, so confirm it with ACAC before test day rather than assuming either way. For a deeper look at what the 75% threshold means in practice, see CIE Passing Score 2026.
The Seven Official Domains in One Pass
ACAC's domain chart lists seven formal exam domains. No percentage weights are published, so there is no official "highest-weighted domain" and no official per-domain question count. One caution: the handbook's shorter body-of-knowledge list has six headings and omits standalone Respiratory Protection, and its "approximately twenty questions per domain" wording does not reconcile with seven domains and 100 questions. The linked seven-domain chart is the controlling source here. For a fuller walk-through, see CIE Exam Domains 2026: Complete Guide to All 7 Content Areas.
Domain 1: IAQ Contaminants and Potential Health Effects
Know the contaminant families an indoor environmentalist is expected to recognize and the health outcomes associated with them.
- Biological contaminants, especially mold and moisture-driven growth
- Chemical contaminants, including volatile organic compounds and combustion byproducts
- Particulates and how exposure routes relate to symptoms
- Linking occupant complaints to plausible sources
Domain 2: Principles of Building Science & the Built Environment
This is the "why does this building behave this way" domain, where moisture, pressure and envelope concepts connect to contamination.
- Moisture movement and condensation in building assemblies
- Pressure relationships between spaces and with the outdoors
- How construction and occupancy patterns create problems
Domain 3: HVAC
Expect questions on how mechanical systems distribute, condition and dilute indoor air, and how failures show up as complaints.
- Ventilation and outdoor air delivery concepts
- Filtration and system components that affect air quality
- Humidity control and its link to biological growth
Domain 4: Equipment Selection, Calibration and Operation
Knowing which instrument answers which question, and whether you can trust the reading.
- Matching sampling and measurement tools to the investigation goal
- Calibration and proper operation
- Interpreting results in context rather than in isolation
Domain 5: Guidelines, Regulations and Standards
Recognize which guidance documents apply, what they actually say, and the difference between an enforceable rule and a guideline.
- Federal and industry guidance referenced in the official reading list
- When no numeric limit exists and professional judgment is required
Domain 6: Remediation
Scope-of-work thinking: containment, source removal, cleaning and verification.
- Controlling the source of moisture before cleanup
- Containment and worker/occupant protection during work
- Post-remediation evaluation concepts
Domain 7: Respiratory Protection
A standalone domain, which is a detail competing study materials sometimes blur. Candidates should be ready for respirator selection logic and program requirements.
- Selecting respirator types for specific hazards
- Program elements under the OSHA respiratory protection standard
- Limits of protection and when higher levels are warranted
The Five-Book Reference Shelf
ACAC's CIE study guide lists five references. The guide recommends reading the listed texts in full before revisiting selected sections, and notes that its page recommendations are not exhaustive exam coverage. Bibliographic listing does not mean the exam is built chapter by chapter from these books, and the publication dates are not exam-version dates.
| Reference | Edition / Year | Best Matched Domains |
|---|---|---|
| AIHA, Recognition, Evaluation & Control of Indoor Mold | 2nd edition (2020) | 1, 4, 6 |
| EPA, Building Air Quality: A Guide for Building Owners and Facility Managers | 1991 | 1, 2, 3 |
| NIOSH, Respirator Selection Logic | 2004 | 7 |
| Managing Indoor Air Quality | 5th edition (2011) | 1, 2, 3, 5 |
| OSHA, Small Entity Compliance Guide for the Respiratory Protection Standard | 2011 | 5, 7 |
The domain pairings in the right-hand column are a study aid based on each book's subject matter, not an official crosswalk from ACAC. One specific trap: the sibling CIEC credential uses a different edition of Managing Indoor Air Quality. For CIE, use the fifth edition listed above.
Eligibility and Application in 60 Seconds
Passing the exam is only one step. Certification also requires a documented experience record. ACAC describes two routes:
- Route A: a related two-year postsecondary degree, or an equivalent 15 qualifying college credits in engineering, science, architecture, industrial hygiene or a related science field, plus at least one year of documented indoor-air-quality investigation experience.
- Route B: a high school diploma or GED plus at least two years of that experience.
Either way, you must submit four project sheets with academic evidence where applicable and verifiable field experience. Academic credit never eliminates the project documentation, and the FAQ requires at least one full year of actual field experience. No mandatory preparation course or minimum training-hour requirement is published. The multi-area experience minimum that applies to CIEC is not part of the CIE requirement. Full details live in CIE Requirements 2026.
Money, Terms and Renewal
| Fee | Amount (USD) |
|---|---|
| Examination | $100 |
| Certification (includes a $100 nonrefundable processing component, not an extra charge) | $400 |
| Initial total, two-year term | $500 |
| Exam retake | $100 |
| Renewal | $400 |
No separate member versus non-member schedule is published. Optional course charges and training-association discounts are separate from these issuer fees, so don't confuse a course price with the cost of certification. The full breakdown is in CIE Certification Cost 2026.
Renewal: The certification term is two years. ACAC's recertification procedure specifies 40 recertification credits (RCs): 10 for continued field activity and 30 for professional development, plus attestation, a current photo, and retained documentation in case of audit. Note that the handbook uses more general continuing-education wording and the program page mentions 20 professional-development hours per year; the specific procedure above is the most detailed source, but the discrepancy is real.
Exam-Day Logistics
- Scheduling: through ACAC, at a testing center or by online video proctoring.
- Identification: two government-issued IDs, including one photo ID, at the center.
- Arrival time: ACAC's exams page says 15 minutes early; the handbook says 30. Plan for the longer window and you are covered either way.
- Online setup: your own computer, an approved webcam, a private location, and at least 2 Mbps upload and download speed. Phones and tablets are excluded.
- Closed book: no reference materials during the three hours.
Pacing math is simple: 100 questions in 180 minutes leaves about 1.8 minutes per question. For timing strategy and exam windows, see CIE Exam Dates 2026.
Key Takeaway
Passing the exam does not by itself make you certified. Board approval of your application and project sheets is a separate gate, and a state-licensing-only pass does not authorize you to use the CIE designation.
Numbers You Can Quote (and Ones You Shouldn't)
ACAC's 2025 Exam Pass Ratio reports 22 passes from 33 CIE examinations and prints 66%. Two cautions apply. First, the report includes retakes and exams taken solely for state licensing, so it is not a first-attempt rate and not a prediction for 2026. Second, a few prep sites claim ACAC publishes no CIE pass rate at all, which is wrong. The official report exists, with limits. A more careful read is in CIE Pass Rate 2026: What the Data Shows, and a difficulty discussion lives in How Hard Is the CIE Exam?.
ACAC's accredited certification activity as of December 31, 2025 lists 33 applicants, 161 recertifications and 394 current CIE certifications. That is a small, specialized credential community, and the counts describe the certified population, not search demand.
Numbers that don't exist in the sources reviewed: official domain weights, a published scored/unscored split, a 2026 pass rate, and a CIE-specific salary survey. If a site quotes them as fact, be skeptical. For earnings context handled carefully, see CIE Salary Guide 2026.
Sequencing the Domains in a Study Plan
You do not need a generic template here, only a sensible order driven by how the domains depend on each other. Contaminants make more sense once you understand how buildings move moisture and air, and remediation and respiratory protection make more sense once you know the hazards. Adjust the pacing to your own background; a field-experienced candidate may compress Weeks 1 to 3 and spend longer on regulations. A broader plan is in the CIE Study Guide 2026.
Domain 2, then Domain 3
- Read the building-science chapters first; moisture and pressure logic underpins everything else
- Pair with HVAC fundamentals from Managing Indoor Air Quality and the EPA guide
Domain 1
- Study contaminants and health effects with the building-science context fresh
- Use the AIHA mold text for biological contaminants
Domain 4
- Match each instrument to an investigation question
- Practice spotting calibration and operation errors in scenarios
Domains 5, 6 and 7
- Standards and guidelines, remediation scope and containment, then respirator selection logic with the NIOSH and OSHA documents
- Finish with timed mixed sets of all seven domains
Because the exam is closed book and heavily scenario-flavored, finish by testing yourself under time pressure. The CIE practice tests are a good place to find which domains need another pass, and you can return to the main practice test site for fresh question sets as you review.
Who Uses the Credential
The CIE fits professionals who investigate and resolve indoor air quality problems: indoor environmental consultants, building and facility personnel, remediation and restoration professionals, and others whose work touches moisture, mold and ventilation. State licensing and ACAC certification are separate processes. Some states reference ACAC examinations in their mold-related licensing schemes, but eligibility conditions vary and should be confirmed with the regulator directly. In particular, current Florida eligibility for the CIE was not verifiable from public sources reviewed, so check with Florida's licensing authority rather than relying on third-party summaries.
For job-market framing, see CIE Jobs and the cost-versus-benefit analysis in Is the CIE Certification Worth It?. Note that no reliable CIE-specific salary survey or causal earnings premium has been established.
Frequently Asked Questions
The exam has 100 multiple-choice questions with at least four answer options each, delivered by computer over three hours. It is closed book, and the passing score is 75%.
No. ACAC lists seven official domains but does not publish percentage weights or per-domain question counts. Any site presenting official weights is extrapolating, so prepare across all seven, including the standalone Respiratory Protection domain.
The initial cost is $500: a $100 examination fee plus a $400 certification fee, covering a two-year term. A retake costs $100 and renewal costs $400. Optional prep courses are priced separately by their providers.
Not necessarily. One route combines a related two-year degree or 15 qualifying college credits with at least one year of documented indoor-air-quality investigation experience. The other combines a high school diploma or GED with at least two years of that experience. Both routes require four project sheets.
ACAC's 2025 report shows 22 passes from 33 CIE examinations, printed as 66%. It includes retakes and state-licensing-only exams, so it is not a first-attempt rate or a forecast for 2026.
Renew every two years with a $400 fee and 40 recertification credits: 10 for continued field activity and 30 for professional development, supported by attestation and retained documentation. Sources differ slightly in how they describe the requirement, so confirm the current procedure on ACAC's site.
Keep this sheet beside the official ACAC pages as you prepare, and revisit the CIE Cheat Sheet and CIE Certification overview whenever you need a quick refresher before test day.