Exam at a glance
The CIE-specific mechanics, verified verbatim on the official candidate handbook.
- Questions
- 100 multiple-choice, each with at least 4 options.
- Time / format
- 3-hour, closed-book, electronic exam. No references allowed in the room.
- Passing score
- 75% — a fixed cut score set by the certification board (Modified Angoff method). Not a curve; aim comfortably above it.
- Where
- Delivered at a Kryterion, Inc. testing center — not PSI or Pearson VUE. An online webcam-proctored option exists across ACAC but isn't confirmed for the CIE specifically.
- Results
- Graded electronically; score shown immediately at the center. Final award still needs board approval.
- Cost
- $400 certification (2-year term, includes a $100 processing fee) + $100 exam = $500 total. Retake = $100, no stated waiting period.
- Validity
- 2 years; renew with 40 recertification credits (10 automatic + 30 documented PD hours).
The CIE (Environmentalist) is the 100-question exam. The CIEC (Consultant) is a higher tier — 120 questions, ~8 years of experience — but shares the same 7 domains and same 5 reference books. Make sure you're applying for the CIE.
Am I eligible?
Exactly two pathways, both totaling a 2-year minimum. A degree just substitutes for one of the two years of experience. There is no prerequisite course.
- A 2-year post-secondary degree or equivalent (15 credit hours) in engineering, science, architecture, industrial hygiene, or a related science field
- + 1 year of documented field experience conducting IAQ investigations
- No degree required (HS diploma or GED)
- + 2 years of documented field experience conducting IAQ investigations
Your ERMI/mold, water, radon, and IAQ assessment work at BioDwell is exactly the "documented field experience conducting IAQ investigations" the pathways describe — but the ACAC board decides what counts. If your degree/credits + tenure sit near the line, call ACAC before you pay.
You submit a notarized form, employer affidavits, four project sheets, and transcripts; you have 90 days to complete the process, and the board meets only about every 4 weeks to award the credential after you pass. Start the application now so experience verification isn't the bottleneck on exam day — and know the certificate itself may land a few weeks after your pass.
What's actually tested
Seven domains (A–G), no published per-domain weighting — treat them as roughly equal. Cards flagged in red are your likely stretch zones: things you do by feel but have never had to name on a test.
Biological, chemical, and radon contaminants — their sources, health effects, and exposure-reduction methods. Your turf; the gap is textbook naming.
Pathways & driving forces (stack effect, wind, pressurization, diffusion) across 4 building types. The exam wants the why in formal terms.
Design, components, ventilation, pressurization, diagnostics. Prime source of calculation questions — cfm/person, air changes per hour.
Sampling/monitoring, and specifically the calibration protocol steps and the data-interpretation statistics — the formal side of what you already do.
Who issues what — EPA guidance vs. OSHA regulation vs. consensus standards — plus the ACAC Code of Conduct. Most divorced from fieldwork, most drillable.
Documentation, containment engineering, microbial vs. non-microbial techniques, post-remediation verification. You write PRVs — lean into the containment formalism.
Narrow and free-point-rich: assigned protection factors, fit-testing, medical evaluation, respirator selection. Maps to two free references.
Ignore any "≈20 questions per domain" claim — 7 × 20 = 140, more than the 100-question CIE. Study all seven; don't gamble one is "20 questions."
The free reference library
The exam is built on these 5 books. Three are free government PDFs — download them today. The two paid books have no legitimate free full text; interlibrary-loan them this week.
A genuinely free path covers 3 of 5 references plus every resource below — enough to own Domains B, C, E, and G. The two paid books are essential with no legitimate free full text. Cheapest route: interlibrary-loan both (start the niche AIHA request in Week 1). If ILL falls through, buy at minimum the ~$63 Hansen & Burroughs and lean on your professional mold knowledge to skim the AIHA text — a calculated risk on a closed-book exam.
Free practice & video
There is no official ACAC practice exam — the CIE tests broad industry knowledge, not a course. Ignore any vendor "pass guarantee." These are the genuinely free reps.
Built to fill exactly this gap — a multiple-choice drill across all 7 domains with shuffled options, instant explanations, an exam-simulation mode, and saved progress. → Open the CIE Practice Exam →
Free EPA training — ACAC-recognized
Flashcards & practice questions — overlapping certs
Free video libraries
The 4-week plan
~1 hour on weekdays + one 2–3 hr weekend block ≈ 9–11 hrs/week. Tick tasks as you go — your progress saves in this browser. Don't re-learn the fieldwork; spend the hours on standards, terminology, calculations, and protocol order.
WEEK 0Admin first — 30 min, before you study a page›
WEEK 1Free gov backbone + standards/ethics Domains E, G, half of B/C›
WEEK 2HVAC, building science & calculations Domains B, C, D›
WEEK 3Contaminants, health effects & remediation Domains A, F — home turf›
WEEK 4Integration, weak-spot repair & simulation›
Test-day tips
Distilled from ACAC's own guidance and community accounts.
Read the reference texts in their entirety — not just the assigned pages. ACAC states outright that limiting study to specific pages "will put you in danger of failing," and that the exam "assumes a comprehensive knowledge of each reference text." The focus-page lists mark where the density is, not the boundary of what's fair game.
It's closed-book — build recall, not bookmarks. Nothing goes in the room with you. Practice recall (flashcards, calculations from a blank page), not just recognition.
75% is a fixed bar, not a curve. The Modified Angoff cut score is criterion-referenced — there's no grading up. An experienced inspector data point: 85 on the CIE. Clear it with margin.
Beware "it was easy" survivorship bias. The credential is experience-gated, so everyone who passed already did this daily. That describes you — but the difficulty is real in the formal-knowledge layer, which is exactly where your prep goes.
Pace for 100 questions in 180 minutes (~1.8 min each — generous). First pass: answer everything you're sure of; flag and return rather than stalling. The risk is second-guessing, not the clock.
Ignore vendor "pass guarantee" pressure. ACAC administers the exam independently; no course vendor has or controls the questions. There is no official practice test.
Confirm these directly with ACAC
The official mechanics above are verified from acac.org. These few items were thin or silent in the research — worth a 5-minute phone call before you rely on them.