James Petersen has nearly 40 years of experience engineering HVAC and plumbing systems across various building types. As the engineer-of-record for numerous large buildings, he has successfully reduced loads for space heating, cooling, and dehumidification to just 25% of conventional expectations. Petersen believes that eliminating or significantly reducing these loads is "good engineering." For buildings driven by external loads, he optimizes building enclosures and designs efficient HVAC systems. His designs are characterized by low embodied and operational carbon, low capital and operational costs, simplicity, low capacity, minimal space requirements, reliability, durability, and ease of maintenance. These systems are also quiet and enhance occupant health and comfort.

James is nationally recognized for his holistic approach and frequently shares his expertise with audiences, often surprising building professionals with his integrated methodology. He collaborates closely with project teams, prioritizing enclosure optimization before designing responsive HVAC systems. Currently, James serves as the Board President of PHMass.