Lennox has announced a leadership transition in its Building Climate Solutions segment. Joe Nassab, Executive Vice President and President of Building Climate Solutions, will step down from his current role at the end of 2026 and remain with the company as a strategic advisor. Geoff Dethlefsen, currently Vice President and General Manager of Lennox Commercial HVAC, will take over the segment on January 1, 2027.
Nassab joined Lennox in 2010 as Vice President and General Manager of Allied Air. In 2022, he became head of the North American Commercial Heating and Cooling segment, later renamed Building Climate Solutions. During his tenure, the segment expanded its commercial equipment and services capabilities through the acquisition of AES and investments in manufacturing, distribution, and customer experience.
In his advisory role, Nassab will support Building Climate Solutions and help coach and develop general managers and future company leaders. Lennox CEO Alok Maskara said the transition would allow the company to continue benefiting from Nassab’s industry experience.
Dethlefsen joined Lennox in 2024 with more than 20 years of experience in industrial manufacturing, strategy, and business operations. Under his leadership, Lennox Commercial HVAC increased revenue and margins, improved operations, and opened a manufacturing facility in Saltillo. Before joining Lennox, he held executive positions at Hammerforce USA and Professional Grade Trailers, as well as leadership roles at Flowserve Corporation and Boston Consulting Group.
“I am honored to lead Building Climate Solutions and build on the strong foundation Joe and the team have established,” said Geoff Dethlefsen, incoming Executive Vice President and President of Building Climate Solutions. “We will remain focused on serving our customers, strengthening execution, and capturing the significant growth opportunities ahead.”
