Lennox International Inc.

Lennox International Inc. is an American manufacturer and distributor of heating, ventilation, air conditioning, and refrigeration (HVACR) products, serving residential and commercial customers across North America and generating $5.2 billion in revenue in fiscal 2025. Founded in 1895 by Dave Lennox in Marshalltown, Iowa, the company has grown from a railroad machine shop into one of the three dominant players in North American residential HVAC, alongside Carrier and Trane, with a growing commercial platform that is quietly becoming the most interesting part of the business.

This is a story about a premium HVAC franchise navigating a year of dislocation while executing an operational transformation that is starting to show up in the numbers — unevenly. The residential business, still the majority of revenue, is working through a post-regulatory-transition hangover that has compressed volumes but preserved pricing power. The commercial business, smaller but faster-growing, is delivering some of the best unit economics in the sector. The file turns on a single question: whether the Building Climate Solutions engine can grow fast enough to carry the enterprise through what might be a longer-than-expected residential reset, and whether the self-help margin story has another leg.

The 2025 refrigerant transition from R-410A to R-454B was the industry's defining event, pulling demand forward into 2024 and leaving 2025 with destocking headwinds. Lennox used the disruption to push through a meaningful mix upgrade — the full conversion to new, higher-efficiency products carried price — but volumes suffered. The first quarter of 2026 offers the first clean read on post-transition demand, and the signal is mixed: stabilization, not recovery. The bears see a cyclical peak in margins. The bulls see a structurally more profitable Lennox that has only begun to harvest the benefits of its transformation. Both have evidence.