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HVAC Expert Witness & Peer Review

HVAC Expert WitnessJohn Melvin, P.E.  ·  Licensed Mechanical Engineer

Thirty years of HVAC and plumbing engineering practice. Independent expert witness analysis for construction defect, personal injury, and insurance subrogation matters — retained by attorneys and insurers across the Mountain West and beyond.

Discuss Your Matter Who I Help
30+Years of Practice
9PE Jurisdictions
$300M+Projects as EOR
LEEDAccredited Professional
Who I Work With

Retained by Attorneys and Insurers

JM Engineering accepts retention by plaintiff counsel, defense counsel, and insurance carriers. All engagements are independent — compensation is never contingent on outcome or opinions rendered.

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Litigation Attorneys

"I need a qualified HVAC expert who can write a solid report and hold up under cross-examination."

Available for retention by both plaintiff and defense counsel in construction defect, personal injury, and insurance coverage matters. Engagements include document review, site inspection, written analysis, and deposition and trial testimony. John's consulting engagements have resolved without proceeding to deposition or trial testimony — a reflection of the clarity and thoroughness of his written analysis.

Construction defect · Personal injury · Standard of care · Daubert-qualified · Rule 702

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Insurance Carriers & Subrogation Counsel

"We need to determine whether this HVAC or plumbing loss was caused by a design defect, installation error, or deferred maintenance."

Technical analysis for carriers and subrogation counsel evaluating HVAC and plumbing losses. Common matters include water damage, freeze-up losses, condensate failures, carbon monoxide exposure, Legionella, hot-water scalding, and equipment failures. Written findings formatted for coverage decisions and subrogation recovery.

Subrogation · Coverage disputes · Cause & origin · Personal injury · Property damage

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Not looking for an expert witness? Peer review, forensic engineering, and pre-litigation design review are handled through Axiom Engineering Group, PLLC — John's full-service SMEP engineering firm.
Visit AEG →
John Melvin, P.E. — HVAC Expert Witness, Licensed Mechanical Engineer
John Melvin, P.E. Licensed PE · HVAC Expert Witness · JM Engineering, PLLC
Background

Engineering Practice Since 1992

John Melvin is a licensed Professional Engineer with over thirty years of continuous HVAC and plumbing practice — beginning immediately upon receiving his B.S. in Mechanical Engineering from Montana State University.

He is the founder of Axiom Engineering Group, PLLC, a multi-state SMEP firm, and previously founded JM Engineering, PLLC (2002–2022). He has served as Engineer of Record on healthcare, K–12, higher education, museum, civic, hospitality, and high-end residential projects across the Mountain West — with aggregate reported construction values exceeding $300 million.

His forensic engineering work draws directly on hands-on construction administration experience: weekly site visits, submittal review, RFI response, and commissioning — not just design-table analysis. Opinions on standard of care, design deficiency, code compliance, and causation are grounded in active design practice and the realities of how buildings actually get built.

John's consulting engagements have resolved without proceeding to deposition or trial testimony — a reflection of the clarity and thoroughness of his written analysis.

Active PE Licenses

Montana
California
Colorado
Idaho
Maine
New York
Utah
Wyoming
Nevada

NCEES Council Record on file — additional jurisdictions available via comity upon formal retention.

Technical Areas of Expertise

  • Forced-air, hydronic, radiant, chilled-beam, VRF/VRV, and geothermal systems
  • Central plant — boilers, chillers, cooling towers, bore fields
  • Load calculations, equipment sizing, and capacity analysis
  • Domestic water, sanitary, storm, and specialty plumbing
  • Code compliance — IMC, UMC, IPC, IECC, ASHRAE 90.1 / 62.1
  • Construction administration — submittals, RFIs, site inspection
  • Post-occupancy performance analysis and failure investigation
  • Building energy modeling and LEED compliance
What I Do

Forensic Engineering & Peer Review Services

Available for retention by plaintiff counsel, defense counsel, and insurance carriers. All engagements are independent — compensation is never contingent on outcome or opinions rendered.

01

Litigation Document Review

Review of construction drawings, specifications, submittals, RFI logs, O&M manuals, and maintenance records to establish what was designed, what was approved, and what was installed. Provides the evidentiary foundation for expert opinions.

02

Site Inspection & Investigation

Physical inspection of installed HVAC and plumbing systems — equipment, piping, ductwork, controls — to evaluate workmanship, code compliance, and conformance with construction documents. Root cause analysis of failures and defects.

03

Written Expert Reports

Detailed written opinions on causation, code compliance, standard of care, and system performance. Structured to meet Federal Rule of Evidence 702 and Daubert reliability standards, and formatted for disclosure under Fed. R. Civ. P. 26 and comparable state rules.

04

Deposition Testimony

Expert deposition testimony on HVAC and plumbing engineering standards, design deficiencies, installation defects, and system failures. Available across all licensed jurisdictions.

05

Trial Testimony

Court appearance and expert testimony explaining complex mechanical engineering issues in plain language for judge and jury. Thirty years of practice means opinions grounded in real field experience — not just textbook analysis.

06

Rebuttal & Response Opinions

Review of opposing expert reports and written rebuttal opinions identifying technical errors, unsupported conclusions, and deviations from accepted engineering standards and applicable codes.

Looking for peer review or pre-litigation design review? Those services are provided through Axiom Engineering Group, PLLC — John's full-service SMEP engineering firm serving architects, owners, and contractors.
Visit AEG →
Insights

HVAC Engineering & Peer Review

Technical guidance for litigation attorneys and insurance carriers on HVAC and plumbing engineering issues that arise in construction defect, personal injury, and coverage matters.

For Attorneys

How Carbon Monoxide Claims Are Evaluated: What Attorneys Need to Know About HVAC Expert Analysis

Carbon monoxide exposure cases involving HVAC systems require a mechanical engineer who can trace the source — flue gas spillage, backdrafting, improper venting — and establish whether the condition resulted from design error, installation defect, or deferred maintenance.

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For Attorneys

Why HVAC Systems Must Be Designed to Manufacturer's Written Instructions — and What Happens When They're Not

Manufacturer's installation and application instructions are not suggestions. When an HVAC system fails and those instructions weren't followed — wrong clearances, incorrect refrigerant charge, improper venting, unapproved controls — a mechanical engineer can establish exactly where the deviation occurred and whether it caused the loss.

Read more
For Insurance Carriers

What Insurance Carriers Should Ask When Evaluating an HVAC or Plumbing Loss

Not every HVAC or plumbing loss is what it appears to be. Before closing a claim or pursuing subrogation, carriers should understand whether the loss stems from a covered cause — design error, installation defect, or maintenance failure — and what evidence a mechanical engineer needs to make that determination.

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For Attorneys

What to Look for in an HVAC Expert Witness — and What to Ask Before You Retain One

Not every PE has forensic experience. Here are the questions that separate a strong HVAC expert from a credentialed witness who will fall apart under cross-examination.

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Technical

When HVAC Causes Moisture Damage: How Engineers Determine Root Cause

Moisture damage in buildings is frequently blamed on the envelope — but HVAC systems are a common culprit. Condensate failures, duct leakage, and improper ventilation all cause water damage that looks like a roofing problem.

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Technical

Geothermal System Failures: Design Problems vs. Installation Defects

Ground-source heat pump systems fail for two very different reasons — and the liability sits in different places. Here's how a forensic engineer separates an undersized bore field from a poorly installed loop.

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For Attorneys & Engineers

Standard of Care in Mechanical Engineering: What It Means, How It's Measured, and Why Contract Language Can Create Liability

The standard of care is what a reasonably competent mechanical engineer would do under similar circumstances — not a guarantee, not perfection. Engineers who use words like "guarantee," "all," or "required" in proposals and contracts inadvertently elevate their legal exposure far beyond what the standard of care requires. Here's what that means in litigation.

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Matters

Types of Cases

Retained on matters involving commercial, institutional, and high-end residential buildings across the Mountain West and beyond.

Design Deficiency Claims

Evaluation of HVAC and plumbing design against the applicable standard of care, code requirements, and industry standards including ASHRAE 90.1, 62.1, IMC, and IPC.

Construction Defect Litigation

Inspection and analysis of installed systems for improper installation, code violations, substandard workmanship, or deviation from approved drawings and specifications.

Equipment & System Failures

Root-cause analysis of HVAC and plumbing failures — including insufficient heating or cooling, hot-water scalding injuries, carbon monoxide exposure, Legionella and indoor air quality, mold growth from condensation or duct leakage, and premature equipment failure.

Water Intrusion & Moisture Damage

Investigation of moisture-related damage attributable to HVAC deficiencies — improper ventilation, condensate management failures, duct leakage, or humidification errors.

Insurance Coverage & Subrogation

Technical analysis for insurance carriers and subrogation counsel evaluating whether HVAC or plumbing losses stem from design error, installation defect, deferred maintenance, or ordinary wear. Common matters include water damage, freeze-up losses, equipment failures, and personal injury claims.

Personal Injury & Premises Liability

Forensic engineering analysis for personal injury matters involving HVAC and plumbing systems — including hot-water scalding, carbon monoxide poisoning from improperly vented combustion appliances, Legionnaires' disease from cooling towers or domestic water systems, and slip/fall injuries related to mechanical equipment.

Energy Performance Disputes

Analysis of whether mechanical systems perform in accordance with energy code, modeled projections, or contract requirements — including LEED certification disputes.

Project Experience

Building Types & Project Categories

Thirty years of design, construction administration, and forensic work across the project types where HVAC and plumbing disputes most commonly arise.

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Healthcare & Medical

Hospitals, clinics, surgical suites, clean rooms, pharmacy compounding spaces, and outpatient facilities. HVAC expertise covers pressure relationships, infection control ventilation, redundancy, and code compliance under FGI Guidelines and ASHRAE 170.

Notable: Shodair Children's Hospital · St. Patrick Hospital (10-year program) · UM Curry Health Center

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K–12 & Higher Education

Public schools, university classrooms, research laboratories, and student health facilities. Particular depth in ventilation per ASHRAE 62.1, energy compliance under IECC, and the operational realities of district-managed buildings.

Notable: Missoula County Public Schools $120M bond program · Santa Clara University Library · Montana State University

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Museums & Civic

Museums, libraries, courthouses, and public buildings — including projects with sensitive collections, historic structures, and humidity-controlled exhibit spaces.

Notable: UM Museum of Art and Culture (LEED Gold) · Missoula Insectarium · Missoula and Granite County Courthouses

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Hospitality & Resort

Hotels, lodges, resort clubhouses, commercial kitchens, golf and ski clubhouses. HVAC and plumbing in hospitality involves heavy public-area loads, kitchen exhaust, guest comfort, and 24/7 operation.

Notable: White Elephant Hotel Aspen · Crazy Mountain Ranch Clubhouse · Snake River Sporting Club · Victory Ranch · Tributary Resort

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Luxury & Custom Residential

High-end private residences, ranch compounds, and remote estate properties. Systems include geothermal heat pumps, hydronic radiant heat, snowmelt, humidification, and multi-building campus distribution.

Notable: Multi-building luxury residence and horse ranch in Jackson, WY · Luxury residence in Westchester, NY · Luxury residence in Yellowstone Club, MT

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Multi-Family Residential

Apartment buildings, condominiums, townhomes, and mixed-use residential. Multi-family disputes commonly involve unit-to-unit comfort complaints, ventilation balance, domestic hot water sizing, and noise transmission from mechanical systems — all areas of direct design experience.

Numerous multi-family projects designed across the Mountain West. Available for retention on construction defect, design deficiency, and system performance matters.

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Historic & Adaptive Reuse

Renovation of historic structures and conversion of existing buildings to new occupancies. These projects raise distinct mechanical issues — concealed conditions, code-triggered upgrades, integration with existing systems, and historic preservation constraints.

Notable: Historic Hamilton Town Hall (1907) · Barrett Productions · LOGE Camps Missoula (motel-to-boutique-hotel)

Service Areas

Where I Work

Active PE licensure in nine jurisdictions, with concentration in the Mountain West luxury and resort markets. Available for matters in additional states via NCEES comity upon retention.

MT

Montana

Missoula · Big Sky · Whitefish · Helena · Bozeman · Hamilton

Home jurisdiction. Active practice across western Montana with extensive healthcare, education, museum, and high-end residential project history. Headquartered in Missoula.

WY

Wyoming

Jackson Hole · Teton County · Statewide

Active practice in Jackson Hole luxury residential and resort markets, including multi-building estate compounds and ranch projects. Available statewide.

UT

Utah

Park City · Salt Lake City · St. George · Wasatch & Summit Counties

Active practice across the Wasatch Front and Park City. AEG offices in Salt Lake City and St. George provide direct local presence for site work and inspections.

CO

Colorado

Aspen · Pitkin County · Summit County · Front Range

Active practice in Aspen and Colorado resort markets, with experience in luxury residential and boutique hospitality projects.

CA

California

Southern California · Bay Area · Statewide

AEG office in San Diego supports California work directly. Project history includes higher-education and luxury residential matters.

ID

Idaho

Statewide

Active PE licensure. Available for matters across Idaho, including resort and luxury residential markets in Teton Valley and Sun Valley.

NV

Nevada

Statewide

Active PE licensure. Available for matters across Nevada including Las Vegas, Reno, and Lake Tahoe markets.

NY

New York

Manhattan · Westchester County · Statewide

Active PE licensure. Luxury residential project history in Manhattan and Westchester County.

ME

Maine

Statewide

Active PE licensure. Project history includes large remote-site estate work with geothermal systems.

Other jurisdictions: John maintains an NCEES Council Record enabling comity licensure in additional states upon formal retention. If your matter is in a state not listed above, contact directly to discuss.

What Comes Next

After the Case Resolves — Then What?

Winning a settlement or verdict establishes liability. It doesn't fix the building. Once litigation concludes, the real engineering work begins.

01

The Building Still Doesn't Work

A court finding of defective design or installation doesn't automatically result in a properly functioning HVAC system. The building owner still has a building with the same problems — now with money to fix it and a legal record establishing who is responsible.

The forensic findings from litigation become the engineering brief for remediation. What was wrong, specifically, and what does a proper system look like?

02

Retro-Commissioning First

Before any system is redesigned or replaced, a thorough retro-commissioning evaluation establishes exactly what the installed systems are actually doing — and what they are failing to do. This prevents the mistake of replacing equipment that isn't the root problem.

Retro-commissioning measures actual system performance against design intent, identifies control failures, calibration errors, balancing deficiencies, and equipment sizing problems.

03

Redesign & Remediation

Once retro-commissioning identifies the root cause, the path forward is clear: repair what can be repaired, replace what must be replaced, and redesign what was never right in the first place. The goal is a building that finally works as the owner was promised.

Proper remediation requires a licensed mechanical engineer — not just a mechanical contractor following the original flawed drawings.

Axiom Engineering Group, PLLC

John's full-service SMEP engineering firm. Once litigation concludes, AEG provides retro-commissioning, system evaluation, and redesign services to make the building work properly — for building owners, attorneys managing remediation, and contractors executing the fix.

Also available before litigation begins: if you are an architect or design team with concerns about a mechanical design and want an independent review to reduce legal risk, that work is handled through AEG — not JM Engineering.

AEG
Axiom Engineering Group, PLLC
Visit aeg.design

Peer review · Pre-litigation design review · Retro-commissioning · System redesign · New construction M&P engineering

Retention

Let's Talk

Initial consultations are confidential. If you're not sure whether your matter is a fit, reach out anyway — a short conversation will tell us both what we need to know.

A signed engagement letter and retainer are required before any work begins. Compensation is never contingent on outcome or opinions rendered.

Hourly rates are available upon inquiry. All engagements begin with a brief consultation to assess scope and fit.

Additional jurisdictions: John holds an NCEES Council Record enabling PE licensure in additional states via comity upon formal retention.

Get in Touch

Reach out directly or use the scheduling link below to request a consultation.

(406) 550-2817
john@jm-eng.us
www.jm-eng.us
Request a Consultation →

Scheduling link is for qualified matters. Use the chat widget or email first if you're unsure whether your situation is a fit.

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