Herman (“Hank” or “Butch”) Morton Leibowitz, a mechanical engineer and businessman that helped pioneer alternative energy technology, lost his bout with cancer and died on Oct. 1, 2026.
Hank was born on May 7, 1943, to Richard and Minnie Leibowitz in Brooklyn, NY.
Hank is survived by his wife of 61 years, Phyllis Leibowitz; his children, Richard (McKenzy) Leibowitz, Sharon (Pirkka) Penttinen, and Joshua (Suzanne) Leibowitz; his grandchildren, Molly, Sydney, Jack, Sutton, Shayna, Collins, and Judah; and his sister, Lea Adams. A man of few but purposeful words, he was fiercely devoted to his family. He instilled a strong work ethic in his children, who, along with his grandchildren, returned his love and devotion in equal measure.
A brilliant man that loved to learn and teach others, Hank tested into and graduated from Brooklyn Tech, then City College of New York (CCNY - 1965, BS in Mechanical Engineering), then University of Connecticut (UCONN - 1968, MS in Mechanical Engineering), then Rensselaer Polytechnic Institute (RPI - 1977, MBA, Marketing and Finance).
Hank was a recognized expert in advanced thermal energy systems. He began his distinguished career designing jet engines for Pratt & Whitney in Hartford, Connecticut (1965–1973). He later worked at General Electric Research & Development (1973–1978) and Mechanical Technology Inc. (1978–1985) in Schenectady, New York. In 1985, he moved to Northern California and entered the entrepreneurial phase of his career as a principal at the start-up Exergy, where he helped develop and commercialize the Kalina Cycle, an innovative thermodynamic power-generation system (1985–1999). Drawing on 35 years of engineering technology experience, he later founded Waste Heat Solutions to provide consulting services to the energy sector.
Hank loved and was loved by his family and close-knit group of friends, some of which go back to his days of playing stickball in the Brooklyn alleyway of his childhood home. He met Phyllis in the college library and married upon their graduation in 1965. They raised three beautiful children. To paraphrase a friend who shared reflections on the news of his death: Butch was bigger than life, had opinions, created ways for people to think about the world around us with fresh eyes. There will be a hole in the universe without him.
Hank was a great bowler, an avid golfer, a baseball fan. Mickle Mantle was his favorite player. He was a voracious reader and enjoyed discussing and debating the topics of the day. He gave great speeches at family events, and his extended family sought him out for sage advice.
A funeral service is scheduled for 11:00 am on Thursday, October 8, 2026, at King David Memorial Gardens in Putnam Valley, NY. In lieu of flowers, please consider donating in Hank’s name to the American Cancer Society.
Information provided by Yorktown Funeral Home
