Tim Riedle, PE

Vice President - Engineering Operations

Tim is VP, Engineering at iENG and has over 17 years of experience in engineering mechanical systems for a variety of facilities. He specializes in the healthcare market, but is an expert in designing HVAC systems, piping, plumbing and fire protection systems across many industries. Tim brings engineering perspective to projects, clients, and team members in design and construction.

  • Education: B.S. Mechanical Engineering, Southern Illinois University - Edwardsville
  • Registration: Missouri & Illinois
  • Affiliations: Healthcare Facility Design Professional (HFDP) l National Council of Examiners for Engineering and Surveying (NCEES); LEED Accredited Professional, Building Design & Construction (LEED AP BD+C)

Annalise Regan, PE

Vice President – Engineering

Annalise is a licensed Professional Engineer with 17 years of experience in engineering HVAC systems. She is responsible for overseeing the design department as well as the mechanical design of large scale commercial and industrial HVAC and process systems. Annalise brings detail-focused engineering perspective to clients and team members throughout the design process. Prior to working at iENG and icon Mechanical, Annalise was an associate at Jaros, Baum & Bolles in New York, NY where she was responsible for designing the mechanical systems for projects such as the World Trade Center and the Whitney Museum of American Art.

  • Education: B.S. Mechanical Engineering, Villanova University
  • Registration: Alabama, Arizona, Arkansas, Colorado, Connecticut, Delaware, Florida, Georgia, Kansas, Kentucky, Maine, Maryland, Massachusetts, Michigan, Missouri, Nebraska, Nevada, New Hampshire, New York, North Carolina, Oklahoma, South Carolina, Tennessee, Virginia and Wisconsin.
  • Affiliations: ASHRAE (American Society of Heating, Refrigeration and Air Conditioning)

Tim Nehrt, P.E.

Vice President, National Engineering

Tim serves as Vice President, National Engineering for iENG, where he is responsible for overseeing the firm’s national projects. He has nearly 20 years of experience in mechanical engineering and design, including new and renovation construction across a wide variety of industries.

  • Education: B.S. Mechanical Engineering, Southern Illinois University - Edwardsville
  • Affiliations: ASHRAE Member (American Society of Heating, Refrigeration, and Air Conditioning) l LEED Accredited Professional, Building Design & Construction l Missouri Licensed Professional Engineer

Alex Chambers

Vice President - Project Management

Alex has nearly a decade of commercial and industrial experience in mechanical design and construction. He currently oversees iENG’s project management team, helping to ensure projects deliver beyond expectations, on budget and on time.


  • Education: B.S. Mechanical Engineering, University of Missouri - S&T

Nick Griffith

Vice President, Commissioning

Nick has nearly 16 years of experience in start-up, balancing and commissioning of various building systems and maintenance and evaluation of HVAC and building management systems. His background includes overhauling centrifugal and reciprocal chiller compressors; troubleshooting, repair and configuration of variable frequency drives; retrofit and small piping projects; repair and maintenance of commercial and industrial boilers; the assessment of mechanical and heat rejection deficiencies in cooling towers.

  • Registration: ASHRAE Commissioning Process Management Professional l American Hospital Association Certified Healthcare Constructor l Master Mechanical License

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