Sentinel Capital Partners, a private equity firm that invests in promising midmarket companies, announced on October 16, 2025 the sale of NSI Industries’ HVAC division—which includes the market-leading Duro Dyne and Supco brands—to Lennox International for approximately $550 million in cash.
With this divestiture, NSI will refocus as a pure-play manufacturer of branded electrical products sold under iconic names like Bridgeport, Polaris, and Tork. Insulated connectors, fittings, and other high-value-add components with steady, replacement-driven demand will remain the core of NSI’s offering.
“There is an excellent strategic fit between NSI’s HVAC division and Lennox,” said John Van Sickle, a Sentinel partner. “This sale returns NSI to its roots as an electrical products company serving distributors nationwide. Our partnership with NSI’s talented management team builds on the company’s strong record of success, great brands, and reputation for superior service to electrical customers.”
“We’ve been proud to call NSI home for the past four years and look forward to joining the Lennox team in our next chapter of growth,” said NSI’s HVAC President, John MacQuarrie. “We remain focused on operational excellence, product innovation, and delivering exceptional value to our customers.”
Sentinel’s expertise in electrical manufacturing and distribution includes prior investments in ECM Industries (electrical products for construction, maintenance, lighting, irrigation, landscape supply, and gas utility markets) and Power Products (diversified electrical products). Sentinel’s broader industrial manufacturing and distribution expertise includes investments in Chromalox (commercial and industrial electric heating products and systems), Engineered Controls (specialized pressure regulators, valves, and other controls), LTI Boyd (engineered sealing and thermal management components), Roto Metrics (rotary tooling products), Sonny’s (conveyorized car wash systems and related products), and Spectrum Safety Solutions (fire detection and suppression products).
About Sentinel Capital Partners
Sentinel is a leading midmarket private equity firm. Working collaboratively with portfolio companies, Sentinel offers operational resources and strategic advice that help its management teams solve challenges, capitalize on opportunities, and build stronger, more valuable businesses. Sentinel also provides junior capital solutions as a minority investor.
Sentinel focuses on niche markets across the business services, consumer, healthcare services, and industrial sectors. Since its inception in 1995, Sentinel has raised more than $11.2 billion of capital. To learn more, please visit sentinelpartners.com.
About NSI Industries
Headquartered in Huntersville, North Carolina, NSI is a leading manufacturer and supplier of branded electrical components to third-party distributors in the United States and Canada. NSI’s portfolio includes well-respected brands such as Bridgeport, Polaris, and Tork, and the company offers more than 10,000 products throughout North America. For more information, visit www.nsiindustries.com.
About Lennox
Lennox (NYSE: LII) is a leader in energy-efficient climate-control solutions. It is committed to sustainability and creating comfortable, healthier environments for residential and commercial customers. Its innovative portfolio includes cooling, heating, indoor air quality, and refrigeration systems, along with a comprehensive range of HVAC parts, supplies, and services that support the full lifecycle of customer needs. Additional information is available at www.lennox.com. For media inquiries, contact PR@lennox.com.
SOURCE Sentinel Capital Partners
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