Andrew J. Thielen

Andrew J. Thielen, P.E.


Andrew Thielen is an accomplished Mechanical Engineer with more than 39 years of engineering experience. He provides expert consultation to the construction industry, primarily in terms of HVAC, plumbing, district heating, and cooling systems. In addition, he was the primary editor of the State of Minnesota Commercial Energy, Mechanical and Fuel Gas Building Codes used in Minnesota from 2008 to 2014. Andy also performs failure analysis.

Clients seek out Andy for his extensive experience in building construction and his commitment to building a trusting relationship and value to the client.  By pairing his broad background in the construction industry with forensic investigation Mr. Thielen minimizes his clients’ exposure and has saved them large sums of money.

By coupling his forensic investigation skills with his specific knowledge of building energy consumption and building energy modeling Andy has shown if equipment was or was not operational at the time of an incident, determined actual energy efficiency of equipment and saved clients millions in settlement costs.

Andy uses his knowledge of building science and how buildings are constructed to understand how failures can happen in a building with an emphasis on building mechanical and plumbing systems.


  • Contributing editor, National Fuel Gas Code Handbook, Tenth Edition, January 2018
  • Minnesota Commercial Kitchen Ventilation Guidelines, Ventilation Committee of the Inter-Agency Review Council, Fourth Edition, January 2010

ESi's expertise spans dozens of industries and specializations organized across several practice groups, each staffed by dozens of in-house experts with the technical knowledge, hands-on expertise, and courtroom experience required to execute projects for and with our clients from start to finish.

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