IAQ-S Pass Rate 2026: What the Data Shows

What the Pass-Rate Data Actually Shows

Candidates searching for the "IAQ-S pass rate" usually want one number: the percentage of test-takers who pass the Indoor Air Quality Supervisor exam on the first try. The honest answer, based on the official materials reviewed for this article, is that the issuer does not publish one. The International Certification Board (ICB), the Sheet Metal Industry International Certification Board, administers the Indoor Air Quality Supervisor (IAQ-S) credential and documents its passing standard, exam structure, fees and renewal rules. It does not, in the reviewed sources, publish pass or fail percentages.

That absence is itself useful data. It tells you that any figure you see quoted online, such as "70% pass" or "only one in three succeed," did not come from the certifying body's current published materials. This article therefore does not offer a pass percentage. What it offers is everything that can be verified about how the exam is built and scored, which is the information that actually predicts your outcome.

For a broader look at difficulty without invented statistics, see our guide on how hard the IAQ-S exam is, and for the scoring rule itself, the IAQ-S passing score breakdown.

Why There Is No Published Percentage

Several structural features of this credential explain why a clean national pass rate is hard to come by, and why you should be skeptical of any that circulate.

A Small, Employer-Linked Candidate Pool

General supervisor eligibility requires employment by a contractor signatory to a collective bargaining agreement that provides direct NEMIC contributions and is current on its financial obligations. Candidates must also satisfy one of four routes (an engineering degree plus experience, an HVAC associate degree plus experience, ICB IAQ Technician certification, or experience plus an employer recommendation). This is not an open-enrollment exam taken by anyone with a credit card. The pool is specialized and pre-screened, which makes a headline pass percentage a poor guide to your personal odds anyway.

Locally Arranged Administration

Exams are given by an ICB-designated proctor at an ICB-designated site, arranged through the local JATC or training-center coordinator. No separate commercial testing vendor was verified. Without a centralized commercial delivery platform publishing statistics, there is no obvious public aggregation point for results.

Version and Source Confusion

The acronym "IAQ-S" is shared by more than one credential in the wider indoor-air-quality world. Pass rates, fees and domain weights from those other programs do not apply here. A number that is true of a different certification is simply wrong for this one, which is why this article sticks to ICB's own published facts.

The 53-of-70 Line: What You Can Measure

While the pass rate is unpublished, the passing standard is explicit. The exam contains 75 total items: 70 scored and 5 unscored beta items. Passing requires at least 53 of the 70 scored items answered correctly. Since 53 divided by 70 is roughly 75.7%, you should plan to get about three out of four scored questions right. An older ICB manual (Version 210504) described this threshold with a rounded 75% label, but the current threshold to remember is the exact count: 53 of 70.

Because you cannot tell which five items are unscored, you must treat all 75 as if they count. The practical implication is that your margin for error is 17 missed scored questions, a cushion that disappears quickly if you are weak in one of the two heaviest domains.

For more on the scoring rule and how it is applied, review the IAQ-S passing score guide.

Who Sits This Exam, and Why It Matters

Understanding the candidate population explains why this exam rewards field experience and supervisory judgment rather than rote memorization. Candidates typically come from sheet metal, HVAC and testing-and-balancing backgrounds, working for signatory contractors. Some arrive having already earned the ICB IAQ Technician credential, which is one of the four eligibility routes. If you are weighing the credentials against each other, our explainers on what IAQ-S certification is and the full IAQ-S requirements lay out the eligibility pathways in detail.

One point deserves emphasis: local course-admission rules are not the same as ICB eligibility. A local training center may require, for example, that you already hold an IAQ Technician credential to enroll in its course. That local condition does not replace ICB's four alternative routes. Likewise, NEMI's no-prerequisite-certification wording for its training does not waive ICB's eligibility requirements. Confusing these layers is a common reason candidates misjudge their own readiness.

Where the Points Are: Five Weighted Domains

The five Domain lines in the ICB knowledge base are official weighted examination objectives, and they total 100%. They are the best predictor of where your 53 correct answers will come from. Here is how to think about each one for the Indoor Air Quality Supervisor (IAQ-S) exam. For a deeper walk-through, see the complete guide to all five IAQ-S content areas.

*Illustrative arithmetic from the published weights applied to 70 scored items; actual per-domain item counts on a given form are not published.

Format and Testing Conditions That Shape Results

Several conditions of the exam directly influence how candidates perform, and they are worth knowing before you worry about statistics.

Written Exam, Online or Paper

The IAQ-S is a written examination delivered online or on paper under an ICB-designated proctor. NEMI explicitly identifies it as a written exam. Practical, hands-on requirements from other certifications should not be assumed to apply here. The retrieved current sources do not explicitly establish a multiple-choice response subtype, so do not assume a specific question format beyond "written."

Reference Materials

Proctor-approved reference materials may be used, including authorized electronic reference viewing under exam-security restrictions. This does not make the exam unrestricted open-book, and it does not establish remote testing from home. Know exactly what your proctor will permit before test day, and practice navigating your references quickly. Time spent hunting for a formula is time you cannot spend reading the next scenario. Calculator permission was not verified, so confirm it with your coordinator.

Time Limit

The current issuer-linked manual and reviewed issuer pages do not state a national numeric time limit. An older externally hosted ICB exam-details document (Version 2.6) lists this exam at 2.5 hours, but its continued applicability was not verified from a current issuer-hosted copy. Treat 2.5 hours as a planning estimate, not a guarantee, and confirm the actual limit when you schedule.

Scheduling Window

Testing must occur within one year of application approval. The detailed ICB workflow places application and exam registration before approval and release of preparation access, followed by local exam scheduling. See our IAQ-S exam dates and scheduling guide for the mechanics.

Retakes, Waiting Periods and Fees

Since no pass rate is published, the retake policy is the most concrete evidence of how the issuer expects some candidates to need more than one attempt. The waiting periods escalate:

Those waits matter for planning around work schedules and for the one-year testing window that begins at application approval. A first-attempt failure followed by a 30-day wait is manageable; repeated failures stretch the timeline considerably.

On cost, the ICB Fee Schedule lists an initial certification fee of USD 125 for eligible non-SMART applicants, waived for SMART members, with renewal also USD 125 and likewise waived for SMART members. These are certification charges; no universal course tuition, exam tuition, travel or local testing charge was verified, so budget separately for any local training. The full picture is in our IAQ-S certification cost breakdown.

An Evidence-Based Plan Built on the Blueprint

Because the weighted domains are the only hard performance data available, they should drive your schedule. The sequence below front-loads the heavy domains and saves the smaller, supporting ones for reinforcement. It assumes you have already been approved and received preparation access through the ICB-then-NEMI workflow. For a fuller treatment, see the IAQ-S study guide.

Pair this with the one-page reference in our IAQ-S cheat sheet, and use the IAQ-S practice test to find which domains need extra time before you schedule your proctored session.

Source Hygiene: Avoiding Wrong-Credential Numbers

Because the acronym is shared, pass-rate claims are especially prone to contamination. Use these checks before trusting any figure you find:

• Confirm the certifying body. This credential is issued by ICB. A statistic attributed to another organization is not about this exam.
• Prefer the current manual. The ICB Certification Manual cover Version 241024 (approved October 24, 2024) is the current issuer-linked scope document. Older manuals remain indexed and can show outdated details.
• Note the standard editions. The knowledge base names ASHRAE 62.1-2019, 62.2-2019, 55-2017, 170-2017, 52.2-2017 and NFPA 70E-2018. These are the outline's reference editions, not claims that they are the latest; study from the editions the outline names.
• Watch for scope drift. Technician-level blueprints and environmental-investigation topics from other credentials are not IAQ-S domains.
• Be wary of mirrors. Public copies of older manuals are not the current issuer-selected document.

If you are comparing credentials, remember that each issuer keeps its own scope and exam rules. Our overviews of the IAQ-S certification and what IAQ-S is keep those distinctions clear, and the ROI analysis addresses whether the credential justifies the effort.

Frequently Asked Questions