- The Number: 53 of 70 Scored Items
- How the 75-Item Exam Is Actually Scored
- Version Caveats: Which Documents Control
- Turning 53 Into a Domain-by-Domain Target
- Exam Conditions That Affect Your Score
- If You Miss: Retest Waits and Deadlines
- Passing the Exam Is Not the Whole Credential
- A Domain-Weighted Prep Schedule
- Frequently Asked Questions
- The Indoor Air Quality Supervisor (IAQ-S) exam has 75 items, but only 70 are scored.
- Passing requires at least 53 of the 70 scored items.
- Five items are unscored beta questions, so you cannot tell which ones count.
- HVAC Systems (25%) and Method of Procedure (23%) carry the most weight on the blueprint.
The Number: 53 of 70 Scored Items
The International Certification Board (ICB) sets the Indoor Air Quality Supervisor (IAQ-S) passing standard at a raw count, not a sliding scale: you need at least 53 correct answers out of 70 scored items. That is the threshold in the current ICB Certification Manual (cover Version 241024, approved October 24, 2024), and it is the figure to plan around for 2026.
Put another way, you can miss up to 17 scored items and still pass. That margin sounds comfortable until you consider that the exam is written by and for working HVAC and sheet metal professionals, and that the questions test supervisory judgment as much as recall. If you are still sizing up the exam, our guide on how hard the IAQ-S exam is covers the difficulty side in depth.
How the 75-Item Exam Is Actually Scored
The IAQ-S is a written examination, delivered online or on paper, with 75 total items: 70 scored and 5 unscored beta items. The beta items are questions ICB is trialing for future exam forms. They look identical to every other question, which means you should answer all 75 with equal care.
What the beta items mean for your strategy
- You cannot identify them. Skipping a question because it "feels like a beta" is a losing bet; any item could be scored.
- They do not lower the bar. The 53-item threshold applies to the 70 scored questions only.
- Unfamiliar questions are not automatically scored. An oddly worded item may be a beta, but treat it as live and give your best answer.
What is not published
ICB's current sources do not publish a scaled-score conversion for the IAQ-S, and the reviewed official sources do not give a verified pass rate. If you want to see what is and is not known, read our breakdown of the IAQ-S pass rate. For this article, the key point is that the passing standard is a fixed count of correct answers rather than a curve against other candidates.
Version Caveats: Which Documents Control
Several versions of the ICB manual remain indexed online, and a few third-party sites mirror older copies. Using the wrong one is an easy way to study the wrong thing.
| Source | What it says | How to treat it |
|---|---|---|
| ICB Certification Manual, Version 241024 (approved October 24, 2024) | Current knowledge base and 53 of 70 scored items | Controlling reference for scope and passing standard |
| ICB Certification Manual, Version 210504 | Adds a rounded 75% label to 53/70 | Older; do not use as the scope authority |
| Older manual mirrors on third-party sites (e.g., v220426 copies) | Public copies of earlier manuals | Not the current issuer-selected document |
One wrinkle worth knowing: the cover and latest version-control entry of the current manual identify 241024, while an internal document-profile table still shows 240429. No separate 2026 exam-form identifier was verified, so "2026" in this article means "the current issuer-linked manual as of this writing." Always confirm with ICB or your local JATC coordinator before test day.
The knowledge base also names the reference editions the outline relies on: ASHRAE 62.1-2019, 62.2-2019, 55-2017, 170-2017, 52.2-2017 and NFPA 70E-2018. Those are the editions the outline cites, not a claim that they are the newest published editions, so study the editions named in the knowledge base.
Turning 53 Into a Domain-by-Domain Target
Because the score is a single raw count across the whole exam, you do not have to pass each domain separately; the 53 can come from anywhere. But the domain weights tell you where the points are concentrated. ICB's blueprint weights total 100%:
| Domain | Weight | Why it matters for the 53 |
|---|---|---|
| 1. HVAC Systems | 25% | Largest block; ventilation, air distribution and system operation questions anchor your score |
| 2. Instrumentation | 15% | Smaller, but heavily applied: what instruments measure and how to trust the readings |
| 3. Supervising the IAQ Technician | 19% | Judgment questions on delegation, scheduling and measurement review |
| 4. Method of Procedure | 23% | Second-largest; scope, communication, infection control and site safety |
| 5. IAQ Final Report | 18% | Report quality and explaining results to customers |
If you apply those weights to the 70 scored items, HVAC Systems and Method of Procedure together account for roughly half the exam, so a weak showing in either one makes 53 hard to reach. The published weights do not state exact item counts per domain, so treat any per-domain question count as an approximation. For a deeper look at each area, see the full IAQ-S exam domains guide.
Domain 1: HVAC Systems (25%)
The heaviest-weighted domain rewards candidates who can reason about how air moves through a building and how ventilation is verified.
- Ventilation and outside-air concepts tied to ASHRAE 62.1-2019 and 62.2-2019
- Filtration efficiency and MERV review in the context of ASHRAE 52.2-2017
- Air balance, building flush and outside-air calculations
- BAS trend interpretation, sensor performance and ventilation troubleshooting
Domain 4: Method of Procedure (23%)
Expect scenario questions about planning and executing an IAQ investigation or ventilation verification the right way.
- Defining scope and communicating with building stakeholders
- Infection control expectations in settings tied to ASHRAE 170-2017
- Site safety, including electrical safety awareness referenced to NFPA 70E-2018
- Thermal comfort concepts connected to ASHRAE 55-2017
Domains 2, 3 and 5 (Instrumentation at 15%, Supervising the IAQ Technician at 19%, and IAQ Final Report at 18%) together make up the remaining 52%. Instrument calibration and measurement review, delegation and work scheduling, and report review are the supervisory skills that separate this credential from a technician-level one. See our comparison of scope in the what the IAQ-S certification is overview.
Exam Conditions That Affect Your Score
Delivery and proctoring
The exam is administered by an ICB-designated proctor at an ICB-designated site, typically arranged through your local JATC or training-center coordinator. Delivery may be online or on paper. No separate commercial testing vendor was verified; ROC-P is the account and application portal, not an exam vendor.
Reference materials
Proctor-approved reference materials may be used, including authorized electronic reference viewing under exam-security restrictions. That is not the same as unrestricted open-book testing, and it does not mean you can take the exam remotely from home. Because the proctor decides what is approved, ask your coordinator in advance which materials are allowed. Calculator permission was not verified in the sources reviewed, so confirm that too, especially given the calculation-heavy content in HVAC Systems.
Question format
The exam is a written one, and NEMI explicitly describes it that way. The retrieved current sources do not establish a specific response subtype such as multiple choice, so rely on official communication from ICB or your coordinator rather than assuming a format. Practical-skills requirements from other certifications do not carry over.
If You Miss: Retest Waits and Deadlines
A near miss is not the end of the road, but ICB enforces waiting periods between attempts:
| Attempt | Wait before retesting |
|---|---|
| First retest | 30 days |
| Second retest | 60 days |
| Third retest and beyond | 90 days |
Also note that testing must occur within one year of application approval. If you plan a slow preparation timeline, build in a buffer so a retest does not push you past that window. For scheduling mechanics, see our guide to IAQ-S exam dates and testing windows.
Money matters here too. The initial certification fee is USD 125 for eligible non-SMART applicants and is waived for SMART members; renewal is also USD 125 and waived for SMART members. These are certification charges, and no separately itemized universal course, travel or local testing fee was verified. Our IAQ-S certification cost breakdown covers what to budget beyond the base fee.
Passing the Exam Is Not the Whole Credential
Hitting 53 of 70 is necessary but not sufficient. Before you ever sit for the exam, you must clear ICB's eligibility requirements: employment by a contractor signatory to a collective bargaining agreement providing direct NEMIC contributions (and current on its obligations), plus one of four routes:
- An engineering degree and at least one year of HVAC installation/design experience
- A two-year HVAC associate degree and at least three years of that experience
- ICB IAQ Technician certification
- At least three years of HVAC installation/design experience plus a written employer recommendation, with that employer ICB-certified or eligible
SMART membership itself is not mandatory for supervisors; qualifying signatory employment is. Local training programs may add their own admission conditions, such as a technician credential for a particular JATC course, but those do not replace ICB's four routes. The full picture is in our IAQ-S requirements guide.
After you pass, the credential stays valid for two full years from the last day of the quarter in which you were certified. Renewal requires continued eligibility, Code of Conduct compliance, an application before expiration, and 8 accepted CEUs earned during the certification period (one training hour equals one CEU, and 8 units cover all supervisor certifications you hold). Signing reports or otherwise using the credential requires qualifying employment with an ICB-certified contractor.
Key Takeaway
Treat the exam as one gate in a sequence: eligibility, application approval, preparation access, proctored written exam at 53 of 70, then renewal CEUs. Plan each step so a delay in one does not expire another.
A Domain-Weighted Prep Schedule
Because the 53-point target rewards breadth weighted toward HVAC Systems and Method of Procedure, sequence your preparation around the blueprint rather than around chapter order. ICB's workflow places application approval before release of preparation materials, and NEMI's training offering includes the IAQ Supervisor Manual, study guide and online course, so confirm your access before you start the clock.
HVAC Systems first (25%)
- Work through ventilation, outside-air, air-balance and building-flush calculations
- Review filtration and MERV concepts against ASHRAE 52.2-2017
- Practice reading BAS trends and spotting sensor problems
Method of Procedure (23%) and Instrumentation (15%)
- Rehearse scope, communication, infection control and site-safety scenarios
- Review instrument use and calibration, since measurement trust underpins every later domain
Supervising the IAQ Technician (19%) and IAQ Final Report (18%)
- Practice delegation, scheduling and measurement-review judgment calls
- Critique sample reports and practice explaining results to customers
Full-length review
- Take timed practice sets covering all five domains and revisit weak spots
- Confirm reference-material and calculator rules with your proctor
That ordering front-loads the two largest domains while you are freshest, then moves to the judgment-heavy supervisory domains once the technical foundation is in place. For a fuller plan, see our IAQ-S study guide, and when you are ready to test yourself under realistic conditions, try our IAQ-S practice tests. The one-page IAQ-S cheat sheet is a handy final-week refresher.
Frequently Asked Questions
Passing requires at least 53 of the 70 scored items. The exam has 75 items total, including 5 unscored beta items, so you can miss up to 17 scored questions and still pass.
An older ICB manual (Version 210504) attaches a rounded 75% label to 53/70, but the current manual states the requirement as 53 of 70 scored items. Study toward the 53-correct count rather than a percentage.
The retrieved sources describe a single threshold of 53 of 70 scored items and do not describe separate per-domain cut scores. Domain weights (HVAC Systems 25%, Instrumentation 15%, Supervising the IAQ Technician 19%, Method of Procedure 23%, IAQ Final Report 18%) show where the questions are concentrated, not separate pass gates.
The first retest requires a 30-day wait, the second 60 days, and subsequent attempts 90 days. Remember that testing must take place within one year of application approval.
Proctor-approved reference materials may be used, including authorized electronic reference viewing under exam-security restrictions. This is not unrestricted open-book testing, so confirm with your proctor and local JATC coordinator exactly what is allowed before test day.
Knowing the exact bar is the first step to clearing it. Pair the 53-of-70 target with the weighted domain plan above, confirm the details with ICB or your local coordinator, and you will walk into the proctored exam knowing precisely what a passing performance looks like. If you are weighing the career side, our guides on the value of the IAQ-S certification and IAQ-S earnings can help you decide how the credential fits your plans.