Few contractors give a second thought to the byline published on their technical manuals. However, the work of Henry “Hank” Rutkowski, founder of HTR Engineering and a longtime ACCA technical consultant, has set the standards for how HVAC professionals calculate loads, size equipment, and design residential systems.
Rutkowski died on November 11, 2025, at age 82 in Cleveland, Ohio. Though he rarely sought the spotlight, his work influenced HVAC standards, contractor training, and building codes across the industry.
Building the technical foundation of ACCA
Beginning in the early 1980s, Rutkowski played a central role in developing and refining ACCA’s technical manuals, the resources many contractors rely on to design residential HVAC systems. Over the course of his career, he helped produce roughly a dozen manuals, including ACCA’s Manual J®: Residential Load Calculation, which became the industry standard for residential load calculations and is now referenced in building codes across the United States.
Rutkowski wanted contractors to have the information they needed to design systems correctly, said colleague Warren Lupson, who retired from the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) in 2015. His goal was to ensure contractors could provide homeowners and building owners with exactly what they needed: a system that performs as intended.
After meeting Rutkowski in the early 2000s, “I immediately recognized Hank as ‘an engineer’s engineer,’” said Glenn Hourahan, former ACCA vice president of research and technology. Rutkowski approached HVAC design from first principles—physics, heat transfer, and building science—to understand how systems perform in real buildings. Then, he translated the insights into procedures that contractors could apply on the job.
“In my opinion, he was among the top 1% of engineers in the HVAC sector,” Hourahan said.
As the industry advanced, ACCA Manual J’s page count swelled. Hourahan once asked Rutkowski why the eighth edition was so much longer than the seventh. Rutkowski told him the expansion reflected changes across the field—advances in building science, new construction practices and materials, increasingly specialized equipment, and stricter codes.
“The full information—‘the truth’—needed to be presented so that conscientious practitioners could feel comfortable undertaking a proper job in all building applications,” Hourahan said.
For many contractors, the association’s technical resources—especially the manuals Rutkowski helped develop—were a primary reason for joining ACCA, said longtime contractor and committee member John Sedine.
“Some years back, ACCA hired a consultant to take a deep dive into the association to determine what made it tick and why contractors belonged,” Sedine said. “…The overwhelming answer was Technical Services, which were Hank’s manuals and our work in building codes and standards.”
Rutkowski’s influence did not go unnoticed. In 2008, ACCA honored him with the Spirit of Independence Award—its highest individual recognition, reserved for those whose work has left a lasting mark on the professional contracting community.
A demanding educator
Rutkowski also spent years teaching contractors how to use those manuals in the field through ACCA’s EPIC courses and other training programs. The classes were not known for being easy, Lupson said—Rutkowski’s expectations were high, and the exams had a reputation for being incredibly challenging. That, however, was by design. Rather than focusing on whether some got the answer correct, Rutkowski cared far more about whether they understood the process used to get there.
“I met Hank during a five-day ACCA EPIC class,” John Chavez wrote in a comment on Rutkowski’s brief obituary. “I learned that he was a prepper, had excellent math skills, and genuinely did not care how you arrived at an answer or whether it was perfectly correct, as long as you understood the process. That was an important lesson for me.”
The man behind the manuals
Rutkowski valued his work with ACCA in part because it gave him the freedom to spend time on other interests.
“Over the years, Hank often remarked how fortunate he was to be an independent contractor to ACCA,” Hourahan said. “By being able to set his own hours and schedule, he had ample time and opportunities to pursue what he called his true passions … sports and being an outdoorsman.”
For decades, Rutkowski competed in tennis leagues and regularly hit the links—sometimes with friends, sometimes alone so he could move quickly and get “36 or more holes in,” Hourahan said. However, his engineer’s brain couldn’t always turn itself off to simply enjoy a hobby.
“He was very interested in NASCAR racing,” Hourahan said. “If questioned, [he] could go on for hours on the re-engineering (tuning and tweaking) of the race cars that involved seemingly very slight modifications that achieved imperceptible advantages for one track or race over another. He remarked several times to me that if he had not gone into HVAC that he would love to have been on a NASCAR pit crew.”
Rutkowski was also an avid fisherman. Sedine recalled a trip to Kaby Lake in Canada, where they spent five days on the water together. “The two of us in a small boat, fishing, catching fish, enjoying the outdoors, shore lunches, and endless conversation,” Sedine said.
Despite his professional impact, Rutkowski largely avoided public attention. “Hank was a private man,” Hourahan said. “Like most people, he desired credit and recognition for his achievements and accomplishments—but he was not into self-aggrandizing.”
Rutkowski eschewed social media and a personal website—remaining, as Hourahan put it, “essentially invisible on the internet … other than his association as the author of ACCA’s many manuals.”
A lasting industry influence
Rutkowski spent much of his career working behind the scenes, focusing on the technical details that determine whether HVAC systems work properly. For many, his work is simply part of the tools of the trade—but it also represents a legacy that will continue to strengthen the HVAC industry.
“Hank will be greatly missed by those of us who knew and understood him,” Sedine said. “All of us appreciate what he has done for the HVAC industry, contractors, and, most importantly, ACCA.”
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