- Property and Building Inspection/Site Review is 70% of the NHIE - study there first.
- The NHIE has 200 questions (175 scored, 25 pretest) with a 4-hour limit and closed-book conditions.
- Passing requires a scaled score of 500 on a 200-800 scale, not a raw percentage.
- ACI certification also requires 250 fee-paid inspections and five verified reports beyond the exam.
How the ACI Path Actually Works
The ASHI Certified Inspector (ACI) credential is awarded by the American Society of Home Inspectors, but the exam itself isn't an "ACI exam" in the branded sense - it's the National Home Inspector Examination (NHIE), developed by the Examination Board of Professional Home Inspectors (EBPHI). This distinction matters because most search results conflate "ACI" with unrelated credentials that share the same acronym. If you're preparing for ASHI's designation, your study target is the NHIE content outline, not a separate ASHI-only test.
Passing the NHIE is a prerequisite, not the finish line. To actually hold the ACI designation, ASHI also requires completion of at least 250 fee-paid home inspections performed in compliance with ASHI's Standard of Practice, submission of five compliant inspection reports for review, and ongoing adherence to ASHI's Code of Ethics. For a full breakdown of every eligibility component, see our detailed ACI Requirements guide.
Registration, Fees, and Scheduling Mechanics
Budgeting for ACI involves two separate payments that candidates frequently mix up:
- NHIE exam fee: $225 per attempt in most US states.
- ASHI certification application fee: $449, paid separately from the exam fee, as part of the ACI certification process itself.
The exam is delivered by computer at proctored testing centers. PSI administers the NHIE in most states, while Pearson handles selected state programs - so confirm which vendor governs your state before you book a seat. Because scheduling logistics and testing windows vary, it's worth reviewing ACI Exam Dates 2026 before you commit to a date. If cost planning is your main concern right now, the ACI Certification Cost breakdown walks through every fee line item, including the $225 exam fee and $449 application fee side by side.
Key Takeaway
Pay the $225 NHIE fee and the $449 ASHI application fee as two distinct transactions - don't assume one payment covers both.
Domain Breakdown: What Gets Tested
The NHIE content outline (effective April 1, 2024) organizes the 175 scored questions into three domains. Weighting is heavily skewed toward field inspection knowledge, which should dictate how you allocate study hours.
Domain 1: Property and Building Inspection/Site Review - 70%
This is by far the largest domain and covers the physical systems you'll assess on any given job. Expect scenario-based questions that mimic real inspection judgment calls rather than simple recall.
- Electrical systems, panels, and grounding/bonding issues
- Structural components, foundations, and framing
- Roofing materials, flashing, and drainage
- HVAC systems and combustion safety
- Plumbing supply, drain, and venting
- Life-safety devices (smoke/CO detection, egress)
- Electric vehicle service equipment (EVSE) installations
- Smart-home and connected-device inspection considerations
Domain 2: Analysis of Findings and Reporting - 20%
This domain tests your ability to interpret what you observed and communicate it correctly in a report - a skill directly tied to the five reports ASHI later reviews for certification.
- Distinguishing defects from normal wear or cosmetic issues
- Prioritizing findings by safety and functional significance
- Writing clear, defensible narrative descriptions
- Applying inspection terminology consistently
Domain 3: Professional Responsibilities - 10%
The smallest domain but not one to skip - it covers the ethical and legal framework inspectors operate within.
- Scope-of-inspection limitations and disclaimers
- Client communication and conflict-of-interest boundaries
- Standard of Practice adherence
- Code of Ethics obligations
For a deeper walkthrough of each domain with topic-by-topic study guidance, see the full ACI Exam Domains Guide.
| Domain | Weight | Question Focus |
|---|---|---|
| Property and Building Inspection/Site Review | 70% | Systems, components, and site conditions |
| Analysis of Findings and Reporting | 20% | Interpreting and documenting defects |
| Professional Responsibilities | 10% | Ethics, scope, and standards |
Question Style and Exam-Day Format
The NHIE consists of 200 multiple-choice questions total: 175 scored questions plus 25 unscored pretest questions mixed in without identification. You get four hours to complete the exam, delivered at a proctored testing center. There's no way to know which questions are pretest items, so treat every question with equal seriousness.
The test is strictly closed-book. Personal notes, reference materials, and calculators are all prohibited at the testing center - everything you'll need must already be memorized or reasoned through using the materials provided on-screen, if any. This closed-book format is a major reason candidates underestimate difficulty; see How Hard Is the ACI Exam? for a candid look at what trips people up.
Passing requires a scaled score of 500 on a 200-800 scale. This is not a percentage of questions answered correctly - the scaling process weights questions differently, so don't try to reverse-engineer a "75% correct" target. For the full mechanics of how scoring works, read ACI Passing Score 2026.
A Domain-Weighted Study Timeline
Generic study methods only help if you point them at the right material in the right proportion. Because Domain 1 carries 70% of the scored weight, it should consume the majority of your calendar - not an even three-way split across domains.
Domain 1 Foundations
- Work through electrical, structural, and roofing systems in depth
- Build flashcards for code-adjacent terminology and defect indicators
- Take domain-isolated practice questions to find weak systems
Domain 1 Continued + HVAC/Plumbing/EV/Smart-Home
- Cover HVAC combustion safety and plumbing venting rules
- Add EVSE and smart-home inspection considerations, since these are newer additions to the outline
- Run timed practice sets to build four-hour stamina
Domain 2: Analysis and Reporting
- Practice writing concise, prioritized defect narratives
- Review how findings should be classified by severity
Domain 3: Professional Responsibilities
- Study the Standard of Practice and Code of Ethics line by line
- Review scope limitations and disclaimer language
Full Review and Simulated Exam
- Take a full-length, timed practice exam under closed-book conditions
- Re-drill any domain scoring below target
If you want a condensed, single-page reference to run through the night before test day, bookmark the ACI Cheat Sheet for a fast recap of must-know facts. And for realistic practice under exam-like time pressure, our practice test platform mirrors the domain weighting described above so your drilling time matches the real exam's emphasis.
After You Pass: Field Requirements for ACI
Passing the NHIE only clears one hurdle. To convert that pass into the ACI credential, ASHI requires:
- At least 250 fee-paid home inspections performed in compliance with ASHI's Standard of Practice
- Submission of five compliant inspection reports for review and verification
- Ongoing adherence to ASHI's Code of Ethics
These field requirements belong specifically to ACI certification - they are not part of every candidate's NHIE eligibility, since some states use the NHIE for licensing purposes independent of ASHI membership. Once certified, maintaining ACI status requires 20 ASHI continuing education credits annually plus continued adherence to professional standards. Don't let the exam distract you from planning the inspection-volume and reporting requirements early - many candidates lose months by starting that clock too late. Our ACI Certification overview lays out the full sequence from exam to full designation.
Key Takeaway
Start logging fee-paid inspections and preparing sample reports well before you sit the NHIE - the 250-inspection and five-report requirements take far longer than the exam itself.
Who Hires ASHI Certified Inspectors
ASHI Certified Inspectors typically work as independent home inspection business owners, or as inspectors within multi-inspector firms serving residential real estate transactions. Buyers, sellers, and real estate agents frequently look for the ACI mark specifically because it signals verified field experience (the 250 inspections) and reviewed reporting quality (the five submitted reports) - not just a passed exam. If you're weighing whether the credential is worth pursuing relative to the cost and time involved, our ROI analysis and salary guide go into that decision in more depth, and ACI Jobs covers where certified inspectors typically find work.
For readers still getting oriented on terminology, our companion explainers - What Is ACI?, ACI Meaning, and What Does ACI Stand For? - clarify exactly which credential this site covers, since the acronym overlaps with unrelated designations elsewhere online.
FAQ
Yes - ASHI does not administer a separate proprietary exam. ACI candidates take the National Home Inspector Examination developed by EBPHI, then complete ASHI's additional certification requirements.
The NHIE has 200 total multiple-choice questions - 175 scored and 25 unscored pretest questions - administered over a four-hour testing window.
You need a scaled score of 500 on a 200-800 scale. This scaled score does not equal a specific raw percentage of correct answers.
No. The NHIE is closed-book; personal notes, study materials, and calculators are prohibited at PSI and Pearson testing centers.
No. Passing the NHIE is one requirement. Full ACI certification also requires 250 fee-paid compliant inspections, five verified reports, the $449 application fee, and adherence to ASHI's Code of Ethics.